Digital chronograph Big 4-digit LCD readout 21-7000 fps measurement Meters per 2nd (mps) or feet per second (fps) readout Stores 9 shot strings with up to 99 shots each in power down memory Testimonial each velocity and shot string information Records average velocity, conventional discrepancy and severe spread Delete individual shots or entire string with the touch of a button Serial information connection port for usage 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 precision of determined speed 1/4×20 mounting hole thread 3/16×16 guide wire size 16x4x3.25 15 mAh power consumption On/off switch Utilizes one 9V alkaline battery (not consisted of) There are lots of optional devices 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 made use of for the record in Bianchi Cup events. Use the ProChrono chronograph to measure the velocities of your airguns, firearms and airsoft weapons. It can do everything!