Electric measuring tools saves you the hassle of having to guess about measurements. There's no cord to restrict you, just make sure you've charged the battery.
From Amazon
Leica Lino L2G – Green Cross-line Laser with Li-Ion Battery and Innovative adapters
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Leica Lino L2 Self-Levelling Green Cross Line Laser (35m - 80m)
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Leica Lino L2G Li-ion Crossline Laser Level - Black & Red