As technology gets more sophisticated, the saying "big things come in small packages" gets truer. Take Bosch's GPL3 for example; the 3 Point Self-Leveling Alignment Laser is pocket sized, only 4-1/8" tall, but you'll be surprised all that it can do. The Patented Diamond-Cut Beam Splitter makes this laser amazingly accurate, and the Easy Field Recalibration keeps the accuracy high and downtime low. Plumb and Level Point Projection accurately transfers and aligns level, plumb, 90 degree and grade pts. Sometimes it can be hard to tell if a surface is 100% level just by looking. Luckly, Bosch incorporated a Smart Pendulum Leveling System, which self-levels and senses out-of-level conditions. No battery lasts forever; when it's time to switch out batteries, do so with the easy access battery compartment. Bosch's GPL3 can provide excellent measurements wherever needed, because it can be mounted magnetically, with straps, or threaded.