Cloud Defensive Cd35001 18350 Rechargeable Battery 3.6V 1000-1100 mAh Compatible W/ UI2 Custom Label Charger/D2 Custom Label Charger Cloud Defensive 18350 unprotected, Flat-Top Cell. Note That The Other Common Brand Weapon Lights Are Not Rated For Un-Protected cells Such as This Battery. Nominal Voltage: 3.6V Rated Capacity mAh: 1000-1100 Size: 18350 Rechargeable: Yes