Like New Competition Electronics ProChrono Shooting Chronograph. This is the one with built in Blue Tooth so you have the ability to communicate with it via their free app. These are invaluable tools for developing your hand loads. I've owned and tested these ProChronos side by side with Pact MK IV, Pro, and LabRadar and they are exactly as accurate for initial muzzle velocity as the others. Comes with spare battery compartment door. I'm in the Greenway and 32nd ST area. Text REDACTED eight 03 eight 3 8 four. I will ship at your expense