Competition Electronics ProChrono Digital Chronograph Features Digital chronograph Large 4-digit LCD readout 21-7000 fps measurement Meters per second (mps) or feet per second (fps) readout Stores 9 shot strings with up to 99 shots each in power down memory Review each velocity and shot string data Records average velocity, standard deviation and extreme spread Delete individual shots or entire string with the touch of a button Serial data connection port for use with remote accessories 32-100 deg. F operating temperature range 250 mSec to 500 mSec time between shots 750 nSec crystal-controlled shot timing resolution +/-1% or better accuracy of measured velocity 1/4"x20 mounting hole thread 3/16"x16" guide wire size 16"x4"x3.25" 15 mAh power consumption On/off switch Uses one 9V alkaline battery (not included)