Description: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 supplyAppearance size (L x W x H): Approx. 5.4 x 4.5 x 1.4cm / 2.12 x 1.77 x 0.55 inchStep-up mode: Input 3.5-28V, output: 1.25-26VOutput voltage is irrelevant to input voltage (input 3.5-28V with arbitrary value, output 1.25-26V with arbitrary value)Step-down 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 anticlockwiseNote: Because of lower switching frequency and input high current, it is normal to use if it has some noisePackage Includes:1 x Step up module