The laser emitters in Leica Lino laser levels are attached to a pendulum that is mounted on high-precision gimbal bearings to ensure that the projected lines are perfectly level, plumb or both.
If the Lino is set up at an angle that exceeds the pendulum's ability to compensate, the Lino will flash its laser lines on and off to indicate that the line is out of level, unless the pendulum lock is engaged.
The pendulum lock does two things: First, it should be engaged when the Lino is not being used to stop the mechanism from being knocked around (and potentially knocked out of calibration) when it is being transported between jobs or if it is dropped.
Second, the pendulum lock enables the Lino to project an angled line, which is useful for jobs like setting out the anchor points for a railing. When the lock is engaged, the Lino will not flash the laser line to indicate that it is out of level.
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