The L4.7 is a rotary laser aimed at the commercial concrete or general contractor working on large jobs requiring the greatest accuracy. It is an improved version of our time tested L4. This instrument self levels in its horizontal mode via a wire hung compensator, and is manually plumbed in its vertical mode. (The optional W1 wall & vertical mount is necessary for vertical operation.) Compared to other lasers in this price range, the L4.7 is more accurate, has greater working range, is the only laser with vertical capability, and has the longest warranty. Accuracy: ±.040" @ 100', Range: 750' working radius with R7 receiver, Leveling system: Wire hung compensator in horizontal mode, manually plumbed in vertical mode. Power: 110 hours of operation on 4 C alkaline batteries(rechargeable batteries are optional), Dust and Water Resistant, 3 Year Warranty L4.7$899.00 W1 Wall & Vertical MountThe W1 allows the L4 to be mounted in its vertical mode. It can be fastened on a tripod or set on the ground. W1$75.00 Rechargeable NiMH Battery Kit - 500-0250MIncludes charger and 4 C NiCd rechargeable batteries 500-0250M$60.00