DROK DC-DC Voltage Buck Converter Volt Regulator 5V-30V to 0.8-29V Step-down Transformer Power Module 5A Constant Adjustable LED Dual Display Amp/Volt Ampere Ammeter Voltmeter Current Volt Tester Dual display of voltage and current; within 5A constantly adjustable output voltage and output current It adopts high-quality LED which is visible and easy to read even under sunshine High-quality chip is used to ensure high efficiency(95% Max), small heating generator and stable output performance Blue LED indicator lights on when the meter is charging while red LED lights on when the meter is full-charge Short-circuit output terminal, then adjust the current output, you can set the current limit.