The next generation of our ProChrono model based on a time proven design that has been measuring "almost anything that shoots" since 1985! Great for firearms, shotguns, archery, airguns, and paintball. Everything is included for outdoor use. For indoor use, we recommend our optional Indoor Lighting System (part# CEI-4100). Requires one 9 volt alkaline battery for operation (not included).Features: On-board Bluetooth connectivity with FREE apps for iOS, Android, Kindle and PC. Internal and external refinements with updates to the circuitry and enclosure design Built in full featured operating system with multiple shot string memory and statistics Sensing system compatible with a wide variety of light conditions and projectiles Fast internal shot clock for accuracy to +/- .5% or better Made in the USA quality at an affordable price 2 year warranty against defects in material and workmanship, and a 1/2 price repair guarantee Over 30 years of experience in chronograph design and manufacturing Replaceable Alkaline 9 volt battery power (not included) for 20+ hours of operation Quality accessories and replacement parts at a reasonable price