XCORTECH X310 is a high quality, multi-function, precise measuring device used for measuring muzzle velocity of BBs fired from firearm replicas with a caliber of 6 mm and 8 mm. The device is powered by two AA batteries (not included in the set), which allows it to be easily carried and used in the field. Compact size and low weight paired with high functionality and intuitive use make it an unrivaled model. Chronograph Features:

_ micro USB power port (only as a means to power it, cannot be charged)

_ better measurement accuracy

_ better reliability

_ highly sensitive IR sensor 

_ low power consumption 

_ powered by 1 AA batteries not included.