# Starting Operation

- Protect the measuring tool from moisture and direct sunlight.

- Do not expose the measuring tool to any 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 Accuracy Check of the Measuring Tool.
  The precision of the measuring tool may be compromised if exposed to extreme temperatures or fluctuations in temperature.

- Avoid substantial knocks to the measuring tool and avoid dropping it. Always carry out an accuracy check before continuing work if the measuring tool has been subjected to severe external influences see Accuracy Check of the Measuring Tool.

- Switch the measuring tool off when transporting it. The pendulum unit is locked when the tool is switched off, as it can otherwise be damaged by big movements.

## Switching On/Off

Before all work, turn the measuring tool on the magnetic rotating mount (3) so that the outlet aperture (1) is not obstructed.

To switch on the measuring tool, slide the on/off switch (2) to the "ON" position. Immediately after switching on, the measuring tool sends laser lines out of the outlet aperture (1).

- Do not direct the laser beam at persons or animals and do not stare into the laser beam yourself (even from a distance).

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.

If you switch off and transport the measuring tool, click it back into place on the rotating mount (3)

- Never leave the measuring tool unattended when switched on, and ensure the measuring tool is switched off after use. Others may be blinded by the laser beam.

GLL 12‑22 G: If the maximum permitted operating temperature of 40 °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.