Stonex Total Station R1 plus is functioned by reflector-less distance measurement, range up to 500m which is applicable for long distance measurement with high accuracy on various kinds of materials or colors such as wall, wire pole, wire, cliff, hill, earth, timber pile, etc. For those targets which are not easy or even impossible to reach, reflector-less distance measurement can complete the measurement task easily. 2 Accuracy Fast distance measurement of 0.5s(Tracking Mode). 20000 Points internal memory Absolute Encoding Disk Dual Axis Compensation SD card Function and USB interface 500m Reflectorless Distance Measurement IP65 water proof rugged and operator friendly. Various surveying programs inbuilt Standard usage temperature range-20to +50C.