Energy-efficient design provides 90 hours of battery life-alkaline standard When used in conjunction with the optional RC601 remote control, the single-axis mode provides matching with self-leveling cross axis for improved accuracy Total operating range of 2,600 ft with + or - 1/16" accuracy @ 100 ft Automatic self-leveling for larger exterior leveling applications Highly rugged design and patented lighthouse seal protect the rotor head and glass, Manufacturer: Spectra Precision Lasers / Trimble