Dear customer: Thank you for choosing my store for shopping. The following are the matters needing attention for shopping:A. Economic transportation: detailed tracking information will not be included. Most of the packages will cause delayed delivery within the expected delivery time, so you need to be patientB. Each product link: There will be different option variants. If you do nt know how to select the product you want, please contact me, I will be honored to solve this problem for you.C. When you receive the package, there is product damage / product problem / error product and shipping problem, please contact me in time, I will solve it for you!D. If you are a wholesaler / distributor, a large number of orders and quantities, to provide you with factory prices, and hope to be honored to reach a partner with you!GOOGZON store: I wish you a happy life! Name : LM2596 DC-DC Buck moduleInput voltage :4V ~ 35VThe output voltage : 1.23V ~ 30VOutput Current :3A( Max)Conversion efficiency:92%( MAX )Output ripple: <30mVSwitching frequency: 150KHzWorking temperature: -forty Five~ +85Size :43mm * 21mm * 14mm(Long*Width*Hight)Features:1. the range of input voltage: 3.2 V to 40 V dc (input voltage must be higher than to the output voltage of 1.5 V above. Can't booster)2. the range of output voltage: 1.25 V dc to 35 V voltage adjustable, high efficiency (92%) largest maximum output current is 3A.Instructions:1. Power (3-40V), power indicator light, the module is working properly.2. Adjust the blue potentiometer knob (clockwise rotation generally boost,counter-clockwise rotationTurn down) and reach with a multimeter to monitor the output voltage required voltage.Note:Current work long hours is recommended for use in less than 2.5A, while adding bulkHeat sink (10W output above),because it is the step-down module, in order to ensure stable output Set,please keep the minimum 1.5V differential.