Measures speed of bullets, arrows, shot, pellets, paintballs, etc. from 30 to 7000 ft per second. Mount on tripod or place on table. Measures 7-1/2×4-1/2×2-3/4" when folded. Made of 20 gauge steel. Weighs less than 2-1/2 lbs. Uses one 9 Volt alkaline battery (not included) for 48 hours of continuous use. Gives numbered shot velocities. Velocity stays on display until you shoot again. One string, from 2 to 32 shot memory. Measures high, low and average velocities, extreme spread and standard deviation. Retrieval of individual shot velocities and statistics. Delete individual shots from memory (with automatic adjustment of statistics). Stereo jack for optional Ballistic Chrony Printer (644-359). For indoors, use the optional Indoor Shooting Light Fixture (432-880). Alpha uses optional Remote Control (286-102).