The GLL 3-50 is a combination laser, meaning it can perform the functions of a plumb bob, spirit level, and square—only faster and more accurately. It projects a plumb and level line from the front (cross lines), a plumb line from one side, and a downward dot from the bottom. The side plumb line is square to the front plumb line so where they meet on the ceiling is a partial cross line. This intersection is directly above the downward dot, so the laser can be used in place of a plumb bob. And of course, it can also be used to project plumb lines, level lines, and square layout.

The GLL 3-50 (first video below) is a less-expensive alternative to the GLL 3-80 (second video below), which without being moved can project plumb, level, and square layout up, down, and onto the four surrounding walls. The GLL 3-50 does more or less the same thing but can only hit two walls at once. There’s a simple fix for that; lay out the first two walls and then rotate the tool to get the ones you missed. It’s particularly easy to do this with the GLL 3-50 because it includes a removable 360-degree rotating base. The base is equipped with a fine-adjustment knob that allows the operator to project a vertical beam on the wall and then adjust its position in very small increments.

According to the tool’s maker, the beams can be seen from 30 feet away (in average lighting conditions) and detected from up to 165 feet away in pulse mode with an optional detector. The on/off switch does double-duty as a pendulum lock so the tool is less likely to be damaged if it falls or gets banged in transit. The GLL 3-50 works best when placed on a tripod or horizontal surface; if you want to hang it from the wall you’ll need to swap the rotating base out with an optional accessory bracket.

GLL 3-50 Specs

  • Modes: plumb and level lines, dot down (can be used as plumb bob)
  • Accuracy: +/- 1/4” at 100’
  • Indoor Visibility Range: 30’
  • Range with detector (not included): 165’
  • Weight: 2.0 lbs
  • Power Supply: 4 “AA” Batteries
  • Self-Leveling Range: =/- 4 Degrees
  • Class II Laser Product
  • Web price: $299
  • Includes: 360-degree base, belt pouch, laser target, L-Boxx inlay, and 4 AA batteries.