"Self-Leveling 3 Beam Laser Dot simultaneously projects 3 self-leveling beams. Magnetic base holds tight to steel framing track. Dust and water resistant. Dimensions L x W x H in. 4 3/16 x 2 9/16 x 4 1/2, Battery Included Yes, Class Rating Class IIIa, Accuracy 1/8 in./50 ft. 2mm/10m, Laser Output Locking mechanism protects inner pendulum during transportation"