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 1/4×20 mounting hole thread 3/16×16 guide wire size 16x4x3.25 15 mAh power consumption On/off switch Uses one 9V alkaline battery (not included) There are lots of optional accessories you can get to customize your Competition Electronics ProChrono digital chronograph. The accuracy of this chronograph is so well-respected in the shooting industry, that this chronograph is used for the record in Bianchi Cup events. Use the ProChrono chronograph to measure the velocities of your airguns, firearms and airsoft guns. It can do it all!