LCD can display input and output voltage, output current and output power; Anti-backflow at the output, no additional anti-backflow diode is needed to charge the battery;It can be boosted or stepped down, the output voltage can be adjusted arbitrarily from 0.5-30V, and the current can be adjusted from 0-4A;Input terminal anti-reverse protection, reverse connection will not burn out; Use buck-boost chip as the main controller, external 60V 75A MOS tube as the switch tube, dual 60V 5A SS56 Schottky for rectification, 60V withstand voltage value, the XL6009 / LM2577 immature solutions on the market (many The withstand voltage of the device is insufficient, and the withstand voltage of the MOS tube and Schottky diode must be the input plus input voltage); The button controls the ON / OFF state of the output, and can be set to ON or OFF by default at power-on; The output ripple is small, with LC filtering; with heat sink, send the module to support the isolation column. Input voltage: 5.5-30V (when the input voltage is 5V, it can also achieve buck-boost, but the voltage and current measurement is not accurate; when it is lower than 4.7V, undervoltage protection) Output voltage: 0.5-30V Output current: can work stably at 3A for a long time, and can reach 4A under enhanced heat dissipation Output power: natural heat dissipation 35W, enhanced heat dissipation 50W Voltage display resolution: 0.05V Current display resolution: 0.005A Conversion efficiency: about 88% Soft start: yes (very high power load module may fail when starting) Input reverse connection protection: Yes Anti-backflow at the output: yes Short circuit protection: yes Working frequency: 180KHZ Colour:blue Material:ABS Size:about 66*48*21mm Package Contents: 3 x 4A buck-boost module Only the above package content, other products are not included. Note: Light 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.