This is an unprotected, flat-top cell. Note that the other common brand weapon lights are not rated for un-protected cells such as this battery. Charge this battery with the UI2 Custom Label Charger or the D2 Custom Label Charger. SPECS Size: 18350 Approximate Diameter: 18.1mm Approximate Length: 35.0mm Manufacturer Rated Typical Capacity: 1100mAh Manufacturer Rated Minimum Capacity: 1000mAh Max Continuous Discharge Current: 10A Nominal Voltage: 3.6V Discharge Cut-Off Voltage: 2.5V Full Charge Voltage: 4.2V Weight: 26g TECHNICAL WARNING: Use caution as misusing or mishandling the battery may cause a FIRE or Mfg: Cloud Defensive