ACETECH AC6000 Airsoft Gun Speed Tester BBS Shooting Chronograph AC6000 is an airsoft chronograph with high quality and accuracy. User-friendly interface with 128*128 pixel OLED in white color Easier to control: Equipped with 4-way push button More durable: IR sensor self-calibration as well as IR sensor calibration in production Friendly UI: Enables user directly select and change ammo parameters in main screen Support Micro-USB(5V/0.5A) power input(no battery charge function) or Use AAA alkaline battery*4 Measures Muzzle Velocity from 30 m/s ~ 400 m/s (90 ft/s ~ 1200 ft/s) Ammo parameter setting supports 5 memory slots Ammo parameter setting from Weight: 0.01g ~ 9.99g Caliber 4.5mm ~ 18mm  25 memory slots for velocity and ROF (Rate of fire) Idling and low battery auto power off function. Pattent Led Lens Design for focusing and diffusing. IR sensor calculate function, Accuracy greatly improved. Auto-calculate MAX, MIN, AVG by shot memory Energy Per Unit Area Calculation FCC, CE, RoHS compliant Tripod Ready mounting hole (Screw for standard camera / camcorder tripods ) Support Micro-USB(5V/0.5A) power input(no battery charge function) ROF range: 100~5000RPM Extra large tube (diameter 36mm) Weight: 290g without battery. Size : L x W x H = 130 x 108 x 61 (mm) A1: Factors do affect speed testing Battery: 1. low voltage, 2. Please use alkaline battery instead of carbon zinc battery CO2 smoke: In case of too much smoke causing the inaccuracy, please stay your muzzle 10cm away from the shooting hole of chrono when use CO2 airsoft gun shooting Over measures range: AC6000 measures muzzle velocity from 30 m/s ~ 400 m/s (90 ft/s ~ 1200 ft/s) A2: Shooting over 10 shots continuously is required, when you do the ROF test.