Features: Available for various batteries like Polymers ,18650 Lithiums ,CellPhone ,Tablet and MP3 Battery The steps up charging board can be connecting to lithiums battery and connecting in multiple sections of lithiums batteries, as long as the voltages is 3.7-5.5V in parallel(only be connecting in parallel, not in series) Charging instruction:Red light flashes when charging; Long red light when full; It have protections functions, protect from over-charging / over-discharging/ over-load ( support charging and discharging at the same time ) Suitable for wide ranges of applications including portable powerbanks, DIY electronics, home devices, and various mobile gadgets, enhancing device flexibility and functionality. Specifications: Component:Plastic Size:Approx.20x18mm/0.79x0.71inch Option Type:Power Supply Module with Type C Port,Power Supply Module with Micros USB Port, Input:3.7V~5.5V (charging red light) Output:5V1A Charging Interfaces:Micros USB/Type C Package Includes: 5pcs 5V Boost Steps Up Power Supply Module note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual item color.