One way adjustable signal generator output. Convenient to provide the pulse signalWorking Perfect,With a logical pen function. For convenient the logic level of test circuitWith one way buzzer. You can test the wires on and off (connect the wires to the power positive and signal input, the wire on - the buzzer sound). You can also test the low-frequency signal (input the signal from the signal input, if there is a signal, the buzzer sound)LM317 voltage regulated power supply kit. Easy to build. Very useful.Plug Type :EU Plug,it applies to Indonesia, Germany, France, Spain, Italy and so on.Plug Type: US Plug, it applies to Canada, India, Mexico, Thailand, Taiwan, the United States, the Philippines and so on.Colour:Photo ColorMaterial:Plastic, metalPackage Contents:1 set x continuous adjustable regulated power supply DIY kit(The accessories have the same random color style and function)Only 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.