set2: 1 x DC Motor Speed Controller + 1 x buzzer alarmRated voltage: 12 VRated current (MAX): 20mAOperating voltage: 3-24VIntermittent sound, mounting bores.Input supply voltage: 6V-28VDCItem size: 1.3 x 2 x 0.4 inchesDuty Cycle adjustable: 0%-100%,without switch.The maximum output power: 80WThe maximum continuous output current :3AAlarm Diameter: 29mm / 1.14 inchAlarm Height: 15mm / 0.59 inch2 Mounting holes Distance: 40mm / 1.57 inch2 wire length: 105 mm / 4.13 inchMin Sound at 10 cm: 95 dBResonance frequency: 3100 +/- 500Operating temperature: -20 ~ + 80 CelsiusColour: Black/whiteMaterial: metal + pc/plasticOperating instruction:Before you attempting to wire the controller, make sure power is off.WARNING: DO NOT REVERSE POSTIVE AND NEGATIVE POWER LOADS.THIS WILL DAMAGE THE CONTROLLER.TO CHANGE MOTOR DIRECTION, INTERCHANGE THE POSITIVE AND NEGATIVE WIRES OF MOTOR.1. Connect wires refer to the "wiring diagram" .2. Turn on the power, and adjust the potentiometer.3. The LED indicates the power up and the speed of motor.Package Contents:1 x DC Motor Speed Controller1 x buzzer alarmOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.