The V3 MagnetoSpeed has: Improved Display A three-button menu system (replaces old toggle switch) Battery options are; (1) 9-Volt or (2) CR123s (replaces 4 AAA batteries) Easy access battery compartment, no need for screwdriver to swap batteries Improved shooting modes, with the ability to now operate with air guns Downloadable firmware updates Advanced data logging and troubleshooting capabilities More compact and rugged display housing Rapid-fire mode with rate-of-fire Re-designed Bayonet Ruggedized strapping system; with metal buckle and triad thumb nut Same proven MagnetoSpeed technology, but with updated sensor Mfg: Magnetospeed SPECS: 9 Volt battery included, can run on 2 CR123 batteries (not included).