Features It has quite low output ripple voltage, for example, 20mV when output is 12V 3A, which is great for powering speaker, audio amplifier, artificial circuit, etc Red&blue light on when constant current charging, blue light on only when constant voltage charging, blue&green light on when almost fully charged, green light on only when fully charged It supports input over-current protection, input under-voltage protection and MOS input anti-reverse protection Input 5V to 30V and it can charge storage battery, lithium battery, AA rechargeable battery, or adjust constant current LED brightness This boost/buck module can step up or step down voltage and maintain a stable output voltage Description:This DC-DC converter module is a buck (step-down) converter combined with a boost (step-up) converter, of which output voltage can be lower or higher than the input. It features small size, high power, high efficiency and stable performance. It would maintain output voltage stability when input voltage is higher, lower than output voltage. Specifications:Input Voltage: 5V~30V   Output Voltage: 0.5V~30V   Output Current: 3A (or 4A if enhance heat dissipation) Output Power: 35W (or 60W if enhance heat dissipation) Output Ripple Voltage: 20mV (at 12V 3A output) Conversion Efficiency: 87~91%(step up); 87~89%(step down)Input Over-current Protection: 10A fuseInput Anti-reverse Protection: High efficiency MOSInput Under-voltage Protection: Yes Output Over-current Protection: Yes Frequency: 180kHz Size: 69*28*21mm / 2.71*1.1*0.82" Package Includes:1 x Module Package List