The Forestor DME 201 uses ultrasonic pulses to determine distance, allowing you to walk 360° around the transponder and receive accurate measurements at the push of a button. Ideal for taking plot radius measurements, the DME is accurate even through thick underbrush and won’t miss borderline trees. The DME 201 can measure distance in English or metric units and measures up to 60’/20m in ideal conditions in feet/10ths or m/cm with an accuracy of ±1%. The DME 201 also features a reverse prism function (BAF feature) which has built-in prism factors of 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 (English) and 0.5, 1.0, 2.0, 3.0 and 4.0 (Metric). The DME 201 will measure the 52.7’ plot radius for a 1/5 acre plot under normal conditions and can be easily calibrated. The distance measuring instrument uses one 9-volt battery, and the transponder uses one AA cell battery (both included). The Forestor DME 201 Complete Unit includes a measuring instrument, transponder, a plot center staff which extends to 54”L and retracts to 25”L, and a threaded adapter for mounting the transponder on the plot center staff or on a standard photographic tripod. When ordering the transponder only, both 09710 and 09711 are required for 360° operation.