21700 Flashlight Batteries

21700 flashlight batteries are high-capacity rechargeable cells suited to the modern high-output lights built around the 21700 size.

The 21700 format has become a favorite in flashlights because it packs more capacity than the 18650 — meaning longer runtime and the headroom to drive bright, high-lumen output. When choosing one for a light, terminal type matters most: many flashlights need a button-top cell to make proper contact, and a protected cell adds a helpful safety margin for everyday use. Some 21700 flashlight cells even include built-in USB-C charging for topping up without a separate charger.

If you're buying for a specific light, check whether it calls for a button top or a flat top, and whether it expects a protected cell, before you order — matching the cell to the light is what ensures it fits and performs.

Key features

• High-capacity 21700 cells for long runtime and bright output
• Protected and button-top options for device compatibility
• Select cells with built-in USB-C charging
• Suited to modern high-output flashlights

Common applications

• High-lumen and high-performance flashlights
• EDC and everyday carry lights
• Search, work, and outdoor lighting
• Any 21700-compatible flashlight or torch