Product description: Input voltage: DC5V Operating voltage: 30mA . Transistor tester control The tester is controlled by a encoder switch. Color: Black material: plastic The encoder switch can have a of 6 operations, short press, long press, left turn, right turn, press and hold left turn, press and hold right turn. A short press in the off state will turn on the power and the test. After a test is completed, if no device is detected. Long press the switch or rotate the switch left or right to enter the function . After entering the function , the left or right switch can select up or down the item, and to enter a certain function item, press the switch short. When it is necessary to exit from a certain function, then long press the switch. Package Contents: 1 x GM328A Transistor Tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.