This is an application of a speed gun.
But speed is only displayed in time after starting with the specified distance until it stops.

The unit of speed can be displayed with the mileage per hour (mph), or the number of kilometer per hour (km/h).

The unit of distance can be specified in feet or meter.
The initial value of distance is 60.5 feet.
This is the distance from the pitcher's plate of baseball to the home base.
Distance can be changed.

The method of stopping measurement can be chosen from two kinds.
One is the method of stopping, if a button is pushed again.
Another is the method of stopping, if a button is detached.