2Pcs Adjustable Regulator Pulse Width PWM DC Motor Speed Controller Switch  Feature:  High efficiency， high torque， low heat generating With reverse polarity protection， high current protection Convenience and easily use  Specification:  Material: PCB and electronic components Input voltage: DC6V - 28V Sustained current: 3A PWM euty cycle: 5% - 100% PWM frequency: 21KHz Module dimension: 50 x 29 x 16 mm \/ 1.97 x 1.14 x 0.63 inch (LHW) (approx) Cable length: Approx 200 mm \/ 7.88 inch  Package included:   2 x PWM motor speed controller switch