Key benefits Durable, stable case for longlasting DIY powerbank builds. Detachable design enables easy battery replacement without soldering. Compatible with standard 18650 cells with flat positive terminals; batteries not included. Clear guidance on polarity and safe setup; must fully charge and activate before first use. Supports quick, straightforward assembly to meet portable power needs; ideal for DIY enthusiasts. Compatibility and requirements Battery type: 18650 cells with flat positive terminal (positive end is flat); do not use button variants. Battery not included; separately. Polarity orientation matters: insert with correct positive and negative alignment. After installing the battery, fully charge and activate the pack before outputting power. No soldering required for battery replacement or maintenance. How to use Verify battery type and polarity before inserting. Insert the 18650 cell into the case with the correct orientation. Secure the battery and ensure the case is properly assembled. Fully charge the pack and activate it before the first power output. Use scenarios Build a portable power bank for camping, travel, or emergency backups. Create a compact power source for cameras, drones, Raspberry Pi, or LED lighting projects. Upgrade or batteries in existing devices by using a replaceable 18650 pack without soldering.