Sports Sensors Swing Speed Radar For Golf & Baseball + Includes Exclusive Golf Bonus DVD Small microwave Doppler radar sensor for measuring golf or baseball swing speeds Calculates clubhead or bat speed within a range of 20 to 200 miles per hour Positions about 8 to 10 inches from tee or suspends from a batting cage or net Includes velocity feedback when trouble-shooting your swing Powered by 3 AA batteries; ideal for both players and coaches/instructors