LCD input and output voltage, output current output power; Input anti-reverse protection, reverse connection will not burn. It can be step-up and step-down, the output voltage 0.5-30V arbitrary regulation, limiting the current 0-4A arbitrary regulation. Output anti-intrusion, the battery charge without additional anti-reflux diodes, Button control output ON / OFF status, and you can set the power-on default is ON or OFF. Specification of 4A Buck-Boost Converter Module Adjustable Buck Boost Board With LCD Display: Input voltage range: DC 5.5-30V (when the input voltage is 5V, the boost and buck can be achieved, but the voltage and current measurement is inaccurate; under 4.7V, under-voltage protection will be activated) Output voltage range: DC 0.5-30V Output current: can stably work at 3A for a long time, when enhancing heat dissipation can reach 4A Output power: 35W (natural cooling), when enhancing heat dissipation can reach 50W Voltage display resolution: 0.05V Current display resolution: 0.005A Conversion rate: about 88% Soft start: Yes, (a large power load module may fail when it is started) Input reverse connection protection: yes Output stop the current from feeding back protection: yes Short circuit protection: yes Working frequency: 180KHZ Size: 66 * 48 * 21mm Mounting hole: 4mm in diameter Package Include: 1 x 4A Buck-Boost Converter Module Adjustable Buck Boost Board With LCD Display