The definitions below describe the level of severity for each signal
word. Please read the manual and pay attention to these symbols.
This is the safety alert symbol. It is
used to alert you to potential personal
injury hazards. Obey all safety
messages that follow this symbol to
avoid possible injury or death.
Read manual symbol - Alerts user to
read manual.
DANGER indicates a hazardous
situation which, if not avoided, will
result in death or serious injury.
WARNING indicates a hazardous
situation which, if not avoided, could
result in death or serious injury.
CAUTION indicates a hazardous
situation which, if not avoided, could
result in minor or moderate injury.
hazardous radiation exposure, electric shock, fire and/or serious
injury. The term “tool” in all of the warnings listed below refers to your
mains-operated (corded) tool or battery-operated (cordless) tool.
your laser tool for your
convenience and safety. They
indicate where the laser light is
emitted by the tool. ALWAYS BE
AWARE of their location when
using the tool.
May 8, 2019. This can lead to persons being blinded.
DO NOT remove or deface any warning or caution labels.
Removing labels increases the risk of exposure to laser radiation.
Use of controls or adjustments or performance of procedures
other than those specified in this manual, may result in hazardous
radiation exposure.
ALWAYS make sure that any bystanders in the vicinity of use
are made aware of the dangers of looking directly into the laser
tool.
DO NOT place the laser tool in a position that may cause
instructions listed below may result in
The following
labels are on
Do not direct the laser beam at persons or
animals and do not stare into the laser beam
yourself. This tool produces laser class 2 laser
radiation and complies with 21 CFR 1040.10 and
1040.11 except for conformance with IEC 60825-1
Ed. 3., as described in Laser Notice No. 56, dated
attachments and accessories
outdoors when lightning
conditions are present.
Do not operate the measuring tool in explosive environments, such as in the presence
of flammable liquids, gases or
dusts. Sparks can be created in
the measuring tool which may ignite the dust or fumes.
Electrical safety
Batteries
can
explode or leak, cause injury
or fire. To reduce this risk,
always follow all instructions and
warnings on the battery label and
package.
DO NOT short any battery
terminals.
DO NOT charge alkaline
batteries.
DO NOT mix old and new
batteries. Replace all of them at
the same time with new batteries
of the same brand and type.
DO NOT mix battery chemistries.
Dispose of or recycle batteries
per local code.
DO NOT dispose of batteries
in fire.
Keep batteries out of reach of
children.
Remove batteries if the device
will not be used for several
months.
Personal safety
If laser radiation strikes your
eye, you must deliberately
close your eyes and immediately turn your head away
from the beam.
Do not make any modifications to the laser equipment.
Stay alert, watch what you
are doing and use common
sense when operating a tool.
Do not use a tool while you are
tired or under the influence of
drugs, alcohol or medication.
A moment of inattention while
operating a tool may result
in serious personal injury or
incorrect measurement results.
Use safety equipment.
Always wear eye protection.
Safety equipment such as dust
mask, non-skid safety shoes,
hard hat, or hearing protection
used for appropriate conditions
Use caution when using laser
tools in the vicinity of electrical
hazards.
Magnets
Keep the tool and
mounting bracket
away from
implants or other
medical devices such as
pacemaker or insulin pumps.
The magnets generate a field
that can impair the function of
implants or medical devices,
which may lead to serious
personal injury.
Keep the tool and mounting
bracket away from magnetic
data storage medium and
magnetically sensitive
equipment. The effect of
the magnets can lead to
irreversible data loss.
Use and care
Use the correct tool for
your application. The correct
tool will do the job better
and safer.
Do not use the tool if the
switch does not turn it on
and off. Any tool that cannot
be controlled with the switch
is dangerous and must be
repaired.
Store idle tool out of the
reach of children and do
not allow persons unfamiliar
with the tool or these
instructions to operate the
tool. Tools are dangerous in
the hands of untrained users.
Maintain tools. Check for
misalignment or binding
of moving parts, breakage
of parts and any other
condition that may affect the
operation. If damaged, tool
repaired before use. Many
accidents are caused by poorly
maintained tools.
Use the tool, accessories,
etc., in accordance with
these instructions and in
the manner intended for the
particular type of tool, taking
into account the working
be performed. Use of the tool
for operations different from
those intended could result in a
hazardous situation.
Service
Have your tool serviced by a
qualified repair person using
only identical replacement
parts. This will ensure that the
safety of the tool is maintained.
Develop a periodic
maintenance schedule for
tool. When cleaning a tool be
careful not to disassemble
any portion of the tool
since internal wires may
be misplaced or pinched or
may be improperly mounted.
Certain cleaning agents
such as gasoline, carbon
tetrachloride, ammonia, etc.
may damage plastic parts.
SAVE THESE INSTRUCTIONS
Intended Use
The measuring tool is intended for determining and checking
horizontal alignments and plumb points.
The measuring tool is suitable for indoor and outdoor use.
The numbering of the product features shown refers to the
illustration of the tool on the graphic page.
(1) Laser beam outlet aperture
(2) On/off switch
(3) Magnetic rotating mount
(4) 1/4” tripod mount
(5) Battery compartment cover locking mechanism
(6) Battery compartment cover
(7) Magnet
(8) Laser warning label
(9) Serial number
(10) Laser viewing glasses
(11) Tripod
(12) Hard Carrying Case
A) Accessories shown or described are not included with the
product as standard. You can find the complete selection of
accessories in our accessories range.
Protect the measuring tool from moisture
and direct sunlight.
Do not expose the measuring tool to any
temperature. The precision of the measuring tool may be
compromised if exposed to extreme temperatures or
fluctuations in temperature. For example, do not leave it in a
car for extended periods of time. If it has been subjected to
significant fluctuations in temperature, first allow the
measuring tool to adjust to the ambient temperature and then
always carry out an accuracy check before continuing work
(see “Leveling Accuracy”, page 18).
an accuracy check before continuing work if the measuring tool
has been subjected to severe external influences (see “Leveling
Accuracy”, page 18).
locked when the tool is switched off, as it can otherwise be
damaged by extreme movements.
To switch on the measuring tool, slide the on/off switch (2) to
the “ON” position. As soon as it is switched on, the measuring
tool emits laser beams from the outlet apertures (1).
extreme temperatures or fluctuations in
Avoid substantial knocks to the measuring
tool and avoid dropping it. Always carry out
Switch the measuring tool off when
transporting it. The pendulum unit is
To switch off the measuring tool, slide the on/off switch (2) to
the OFF position. The pendulum unit is locked when the tool is
switched off.
ing tool is switched off after use. Others may be blinded by the
laser beam.
If the maximum permitted operating temperature of 113 °F (45
°C) is exceeded, the tool shuts down to protect the laser diode. Once it has cooled down, the measuring tool is operational
again and can be switched back on.
animals and do not stare into the laser
Never leave the measuring tool unattended
when switched on, and ensure the measur-
Automatic shut-off
The measuring tool automatically switches itself off after 60 min
of operation.
If the switched on measuring tool is not within the self-levelling
range (the laser points flash continuously), the automatic shutoff is reset to 60 min.
Automatic Levelling
Position the measuring tool on a level, firm support or attach it
to a tripod (11).
To use the bottom laser point, rotate the measuring tool on the
magnetic rotating mount (3) in such a manner that the laser
point can be seen on the floor.
After switching on, the automatic levelling function automati-
cally compensates irregularities within the self-levelling range of
GPL100-30G 50G 11-20.indd 18
±4°. The levelling is finished as soon as the laser points light up
continuously (i.e. no longer flashing) and do not move any more.
If automatic levelling is not possible, e.g. because the surface on
which the measuring tool stands deviates by more than 4° from
the horizontal plane, the laser points will flash continuously and
quickly.
If this is the case, set up the measuring tool in a level position
and wait for the self-levelling to take place. As soon as the measuring tool is within the self-levelling range of ±4°, the laser
points will light up continuously.
In case of ground vibrations or position changes during operation, the measuring tool is automatically levelled again. After
each levelling process, check the position of the horizontal
and/or vertical laser points in relation to the reference points
to avoid errors arising from a change in the measuring tool’s
position.
Accuracy Check of the Measuring Tool
Influences on Accuracy
The largest influence is exerted by the ambient temperature. In
particular, temperature differences that occur from the ground
upwards can refract the laser beam.
Since the temperature stratification is greatest at ground level,
you should always mount the measuring tool on a tripod for
measuring distances of 65 ft (20 m) or more. In addition, position the measuring tool in the centre of the work surface, wherever this is possible.
In addition to external influences, device-specific influences
GPL100-30G 50G 11-20.indd 19
(e.g. falls or heavy impacts) can also lead to deviations. For this
reason, check the levelling accuracy each time before beginning
work.
Should the measuring tool exceed the maximum deviation during one of the tests, please have it repaired by a Bosch aftersales service.
Checking the horizontal levelling accuracy
For this check, you will need a free measuring distance of 16 ft
(5 m) on firm ground between two walls (designated A and B).
– Mount the measuring tool close to wall A on a tripod, or place
it on a firm, flat surface. Switch on the measuring tool.
A
B
16 ft (5 m)
– Aim the horizontal laser beam that runs parallel to the longitu-
dinal axis of the measuring tool at the closer wall A and allow
the measuring tool to level in. Mark the centre of the laser
point on the wall (point I).
– Turn the measuring tool 180° without adjusting the height.
Allow it to level in, then mark the centre point of the laser
beam on wall A (point III). Ensure that point III is as vertical
as possible above or below point I.
– The discrepancy d between the two marked points I and III
on wall A reveals the actual height deviation of the measuring
tool along the longitudinal axis.
The maximum permitted deviation on the measuring distance of
2 × 5 m = 10 m is as follows:
32 ft x ±0.0036 in/ft = ±1/8 (0.115 in)
(10 m × ±0.3 mm/m = ±3 mm)
The discrepancy d between points I and III must therefore
amount to no more than 3 mm.
GPL100-50G: Repeat the measuring process for the two side
laser beams that run along the transverse axis of the measuring
tool. To do this, turn the measuring tool 90° clockwise or anticlockwise before beginning the measuring process.
uAlways use the centre of the laser point for marking. The
size of the laser point changes with the distance.
Use with Attachments
Working with the Tripod (Accessory)
A tripod offers a stable, height-adjustable support surface for
measuring. Place the measuring tool with the 1/4” tripod mount
(4) on the thread of the tripod (11) or a conventional camera
tripod. Tighten the measuring tool using the locking screw of
the tripod.
Roughly align the tripod before switching on the measuring tool.
Attaching using the magnetic rotating mount
(see figures AB)
You can secure the measuring tool to magnetisable materials
using the integrated magnetic rotating mount (3).
u Keep your fingers away from the rear side of the magnetic
rotating mount while attaching the rotating mount to sur-
faces. The strong pulling force of the magnets (7) may jam
your fingers.
Roughly align the magnetic rotating mount (3) before switching
on the measuring tool.
Rotate the measuring tool on the magnetic rotating mount (3)
to make the bottom laser point visible or to project heights with
Store and transport the tool only in the supplied protective case
(12).
Keep the tool clean at all times.
Do not immerse the tool into water or other fluids.
Wipe off debris using a moist and soft cloth. Do not use any
cleaning agents or solvents.
Regularly clean the surfaces at the exit opening of the laser in
particular, and pay attention to any fluff of fibers.
If the tool should fail despite the care taken in manufacturing and
testing procedures, repair should be carried out by an authorized
after- sales service center for Bosch power tools.
In all correspondence and spare parts orders, please always
include the 10-digit article number given on the type plate of the
tool.
In case of repairs, send in the tool packed in its protective case
(12).
ENVIRONMENT PROTECTION
Recycle raw materials & batteries instead of disposing
of waste. The unit, accessories, packaging & used
batteries should be sorted for environmentally friendly
recycling in accordance with the latest regulations.
Robert Bosch Tool Corporation (“Seller”) warrants to the original purchaser
only, that all Bosch lasers and measuring tools will be free from defects in
material or workmanship for a period of one (1) year from date of purchase.
Bosch will extend warranty coverage to two (2) years when you register
your product within eight (8) weeks after date of purchase. Product
registration card must be complete and mailed to Bosch (postmarked within
eight weeks after date of purchase), or you may register on-line at
www.boschtools.com/Service/ProductRegistration. If you choose not to
register your product, a one (1) year limited warranty will apply to your
product.
30 Day Money Back Refund or Replacement -
If you are not completely satisfied with the performance of your laser and
measuring tools, for any reason, you can return it to your Bosch dealer
within 30 days of the date of purchase for a full refund or replacement.
To obtain this 30-Day Refund or Replacement, your return must be
accompanied by the original receipt for purchase of the laser or optical
instrument product. A maximum of 2 returns per customer will be permitted.
SELLER’S SOLE OBLIGATION AND YOUR EXCLUSIVE REMEDY under
this Limited Warranty and, to the extent permitted by law, any warranty or
condition implied by law, shall be the repair or replacement of parts, without
charge, which are defective in material or workmanship and which have not
been misused, carelessly handled, or misrepaired by persons other than
Seller or Authorized Service Center. To make a claim under this Limited
Warranty, you must return the complete Bosch laser or measuring tool,
transportation prepaid, to any BOSCH Factory Service Center or Authorized
Service Center. Please include a dated proof of purchase with your tool. For
locations of nearby service centers, please use our on-line service locator or
THIS WARRANTY PROGRAM DOES NOT APPLY TO TRIPODS AND
GPL100-30G 50G 11-20.indd 28
RODS. Robert Bosch Tool Corporation (“Seller”) warrants tripods and
leveling rods for a period of one (1) year from date of purchase.
THIS LIMITED WARRANTY DOES NOT APPLY TO OTHER
ACCESSORY ITEMS AND RELATED ITEMS. THESE ITEMS RECEIVE A
90 DAY LIMITED WARRANTY.
ANY IMPLIED WARRANTIES SHALL BE LIMITED IN DURATION TO
ONE YEAR FROM DATE OF PURCHASE. SOME STATES IN THE U.S.,
AND SOME CANADIAN PROVINCES DO NOT ALLOW LIMITATIONS
ON HOW LONG AN IMPLIED WARRANTY LASTS, SO THE ABOVE
LIMITATION MAY NOT APPLY TO YOU.
IN NO EVENT SHALL SELLER BE LIABLE FOR ANY INCIDENTAL OR
CONSEQUENTIAL DAMAGES (INCLUDING BUT NOT LIMITED TO
LIABILITY FOR LOSS OF PROFITS) ARISING FROM THE SALE OR
USE OF THIS PRODUCT. SOME STATES IN THE U.S., AND SOME
CANADIAN PROVINCES DO NOT ALLOW THE EXCLUSION OR
LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO
THE ABOVE LIMITATION MAY NOT APPLY TO YOU.
THIS LIMITED WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS,
AND YOU MAY ALSO HAVE OTHER RIGHTS WHICH VARY FROM
STATE TO STATE IN THE U.S., OR PROVINCE TO PROVINCE IN
CANADA AND FROM COUNTRY TO COUNTRY.
THIS LIMITED WARRANTY APPLIES ONLY TO PRODUCTS SOLD
WITHIN THE UNITED STATES OF AMERICA, CANADA AND THE
COMMONWEALTH OF PUERTO RICO. FOR WARRANTY COVERAGE
WITHIN OTHER COUNTRIES, CONTACT YOUR LOCAL BOSCH
DEALER OR IMPORTER.