BAK 21700, 5000mAh, 15A, Flat Top

Both button top batteries I stock for the L21B torches are this same model here. 
 
If you have one of those torches and plan to mount it on a gun, then you must purchase with a button top.
 
Price is per battery
 
Battery specs:
 
- Nominal Capacity: 5000mAh
- Nominal Voltage: 3.6V
- Maximum Voltage: 4.2V
- Continuous Discharge Current: 15A
- Approximate Dimensions: 21mm x 70mm
- Unprotected: Yes
 
Buyers must be aware of lithium safety before purchase. Please read my thorough battery safety guide - here