Note: 21700 batteries are not included in the package and must be purchased separately. Safety and compatibility Reversing the positive and negative terminals can damage the motherboard and protection board. Please observe the correct polarity of the battery terminals. Only 21700 batteries with a flat positive electrode are compatible with this case. Easy assembly and performance Easy assembly with our 21700 battery case. Designed to accommodate six batteries for most power storage needs. Features PD100w super fast charging capability. Use scenarios Home backup power: Use six 21700 cells to create a compact storage pack for power outages or grid fluctuations, with fast charging support for readytouse power. Outdoor and travel: A portable power solution for camping, remote work sites, or emergencies where reliable energy storage and quick recharge are valuable. Onthego device charging: Suitable for applications that require rapid charging of compatible devices through the PD100w capability, while using a compact 6battery configuration.