One centimetre here and there is really not inconsequential, use an electric measuring tool to be safe. No need to look for a power outlet, since it runs on batteries. Just get at it!
From ManoMano
Intelli Tools FMHT1-77357 Red Beam X3R Multi-Line Laser INT177357 - Stanley
ITS
Stanley FMHT177357 FatMax X3R 3x 360 Laser - Red Li-ion Multiline
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