The Valken airsoft chronograph is the ultimate high-tech tool for teching, tuning and safety! Powered by a rechargeable battery (with included charging cable), this compact yet powerful airsoft chronograph unit mounts easily to an included mini-tripod for convenient use anywhere! Capable of being tuned to measure various sizes and weights of projectiles for energy (joules), velocity and free fall measurement, serious airsoft shooters can now use this impressive airsoft Chronograph to fine tune their airsoft guns to shoot how they want, where they want, with whatever projectiles they prefer to use!