Prochrono Digital USB Interface and Purchasecorner Polish Cloth Bundle Pro Chrono USB Interface and Purchasecorner Polish Cloth Bundle. Works with Windows 98,Windows 2000,Windows XP,Windows Vista,Windows 7,Windows 8 This is useful if two chronographs are being used to measure the same projectile in order to validate the results. size display of the velocity readout and the power factor on your computer screen. The size is adjustable to suit the desired viewing distance. Great for showing the results to a group of onlookers. Control all of the chrono functions, read a list of velocities from each shot string and the associated statistics, and print a report. You can also input information for calculating the ammo. power factor and foot/lbs. Uses the computer USB port for a wired connection to the Pro Chrono Digita