A power tool handle has a shaft with a fastening end securing the handle on the power tool and with a free end. The handle has an outer side for supporting a palm of a hand. First and second operating elements are pivotably supported at the shaft about first and second pivot axes, respectively. The first operating element controls a power tool drive motor. In non-actuated position, the second operating element prevents a control action of the first operating element and has an actuating section projecting from the shaft and having a first and a second end. The first end is closer to the fastening end of the shaft than the second end. The second end is closer to the free end of the shaft. The second pivot axis is closer to the first end than to the second end. A trimmer is provided with such a handle.

A method operates a hand-guided processing device having a user-activated operating sensor device with a plurality of different detection positions. The method involves the steps: a) detecting a sequence of activations of the operating sensor device at different detection positions of the plurality of detection positions, and b) when the detected sequence corresponds to a given sequence, calibrating the operating sensor device for at least one detection position of the plurality of detection positions based on at least one of the activations of the detected activations.

Lock off assemblies for trimmers are provided. A trimmer includes a working head; a handle assembly connected to the working head by a connecting member; a trigger connected to the handle assembly and movable between an off position and an on position, wherein the trigger being in the on position causes actuation of the working head; and a lock off assembly. The lock off assembly includes a switch connected to the handle assembly and movable between a safe position and an operate position; and a pivotable extension pivotably connected to the switch, wherein the pivotable extension contacts and blocks the trigger when the switch is in the safe position and the trigger is moved from the off position towards the on position, and wherein the trigger is free to move between the off position and the on position when the switch is in the operate position.