You can use this rotary laser on uneven surfaces, since it's self leveling. The voltage on this rotary laser is 2 volts.
From Data Powertools
Stabila STBLAR160TS LAR 160 Rotation Laser Set 7 Piece
ITS
Stabila LAR160LSET Motorised Self-Levelling Rotating Red Laser with Receiver, Tripod and Staff
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