Signifies Limitless (Infinity Setting) use and application in limitless fields / occupation. Plumb Bob: Several unique racking systems allow the balanced 3D to act as a dynamic plumb bob. Jack Screw: Used to set grades or slopes quickly or to adjust the DMS laser level. Allows instant referencing and top viewing for 3D leveling and DMS laser tracking. Strongest in the world, 5 neodymium rare earth magnets secure the 3D on metal surfaces at any angle., Manufacturer: Checkpoint Professional