Optical sensor OS-02 which you can run on

which you can run on any Windows

and a metal strap with a screw

You can find more details about this model in reviews by Tony Chow

Mounting plate XXL – used for fixing optical sensor on the barrels diameters from 20 mm

Alternatively

Optical sensor OS-02 which you can run onOptical sensor model: OS 02 is mounted on the gun and registers all gun movements during the time leading up to the shot and during the shots execution (the action of pulling the trigger). Sensors weight is 30 grams (including the fixing accessories) and has barely any effect on the balance of the weapon of your choice. SCATT software enables convenient calibration process, so the axis of the sensor and guns sights are correctly aligned, sparing the