Cross Point Reference Lines - Provide easy single-set up track alignment on both floor and ceiling, eliminating the need of two set up points for track alignment which saves time and increases accuracy. Highly-Visible Laser Lines - Three diodes project all points for superior accuracy Built in Magnets - For quick alignment on metal track. Projects Plumb, Level and Square Points - In addition to the conventional 5 laser dots for wall and partition alignment, the GPL5C offers laser cross alignment lines on floor and ceiling which eliminates the need for two set up points which saves time and increases accuracy. Selection Switch - To choose between laser options of: 3 horizontal points for 90-degree alignment and leveling; up and down cross points with 90-degree horizontal point; 5 points with cross points - meets all job needs and save battery life. Smart Pendulum Leveling System - Self-levels, senses and indicated out-of level condition, locks when switched off.