Shooting Chrony F1 Master Chrony Can go with you anywhere, extremely easy to transport. Has all of the qualities of the F1 Chrony plus more! Powered by a single 9 volt battery. Measures the speed of any projectile from 30 feet per second to 7000 feet per second. Measures speed within .5% accuracy. Can go with you anywhere, extremely easy to transport. Has all of the qualities of the F1 Chrony plus more Powered by a single 9 volt battery. Measures speed within .5-Percent accuracy.