LM2577S + LM2596S dual chip modules, DC-DC step up module with wide voltage design, suitable for solar panel and other high fluctuation external input power supply. Step-up mode: Input 3.5-28V, output: 1.25-26V. Output voltage is irrelevant to input voltage (input 3.5-28V with arbitrary value, output 1.25-26V with arbitrary value). mode: Input / Output current (max.): 3A, rated input/output: 1A (Please add cooling fin when working in big current). Voltage regulating mode: (Step-up) Potentiometer rotates in clockwise, (Step-down) Potentiometer rotates in anticlockwise. Specification: Product Name: Step UP/Down Module Material: Electronic Components Size: 6.6x4.7x1.4cm/2.6x1.85x0.55inch (with Digital Display) 5.4x4.5x1.4cm/2.13x1.77x0.55inch (No Digital Display) Package Includes: 1x Step Up/Down Module (with Digital Display) 1x Step Up/Down Module (No Digital Display) Note: Note: Because of lower switching frequency and input high current, it is normal to use if it has some noise.