Create your own portable charging solution with this 18650 DIY Power Bank Metal Storage Case Kit. Designed for makers and electronics enthusiasts, this compact power bank box includes a built-in charging circuit board that converts a single 3.7V 18650 lithium-ion battery into a convenient 5V USB mobile charger. Featuring a durable metal housing, removable battery design, and built-in protection against overcharging and overvoltage, it provides a safe and practical way to build a custom power bank. With a lightweight 90×21mm design, USB 5V/1A output, and multiple color options, this DIY kit is perfect for smartphone charging, portable electronics projects, and custom battery solutions. (Battery not included; compatible with unprotected flat-top 18650 batteries only.)
