Notice: The new tracking number for China Post Ordinary Small Packet Plus can be traced only befor it arrive the airport of your country,please choose China Post Air Mail if you want a full tracking info. Tracking info of  China Post Ordinary Small Packet Plus can be check here : www.17track.net/en Features: The Voltmeter Resolution: ±0.1V The Voltmeter Digital Display Range: 0v-45v The Voltmeter Input Voltage Range: Dc 4v-40v Output Voltage: Continuous Adjustable (1.3v-37 V) Output Current: 2a size :65*35mm Led Digital Voltmeter Tube, The Accuracy Is Adjustable Function, Can Be Aimed At Your Multimeter Adjustable Accurate. Press the key "S1" to let the display show the input or output voltage. when the green led light, it shows output, the red show input. Note: To guarantee the accuracy of the voltmeter , make sure the input voltage above 4V. The input voltage must be 1.5v higher than the output voltage or 1.5v above. Package Content: 1 Pcs x LM2596 Power Module