Locating recessed light cans and pendant boxes during framing is wide open to mistakes, especially on tall sloped ceilings. If those blue pendant lights didn't end up distributed right over the kitchen island, I would be in big trouble. I needed a better tool than a plain old plumb bob (that never stops swinging) and a ladder.
A lot of fancy laser tools have more promise than delivery. This one does one thing and does it well. It really worked for me.
Here's the official dope on this tool from Stanley:
77-189 PB2 - FatMax Self-Leveling Laser Plumb Bob
Features and Benefits
This self-leveling laser plumb bob creates an accurate, highly visible plumb reference instantly
One button instantly transfer point from floor to ceiling
Creates an accurate, highly visible plumb reference instantly
Unique magnetically dampened self-leveling system settles plumb bob up to 20 times faster than conventional methods
Combines traditional plumb bob ease-of-use with laser-accurate alignment
Ideal for stud plumbing and alignment, ceiling joist and rafter alignment, establishing diagonals and footings for decks and patios, aligning and plumbing pipe or conduit, transferring points from floor to ceiling, fixture installation and alignment, e.g. lights, fans, etc
Magnetic base
Includes: Laser, carrying case, instruction manual
Working Range: Up to 100 Visible Range
Working Environment: Designed for Interior use
Leveling Accuracy: UP +/- 1/8-in @ 50' DOWN: +/- 1/4-in @ 50'
Leveling Type Pendulum Self Leveling, +/- 5 degrees in any direction
Laser Diode: Three 635-670nm
Laser Class: Class 2M/3R
Batteries: 3 AA Alkaline batteries (included)
Battery Life: Up to 60 hours intermittent use
Warranty: 12 Months