The Efest Green 26650 4200mah 50Amp Batteries are the newest in the market with longer lasting Battery Life. This battery is perfect to use with most 26650 mods. Efest Green 26650 4200mAh Battery Features: Capacity: 4200mah Cycle Life: 300 Times Top: Flat Top Bottom: Non-Protected Diameter: 26.22mm Length: 65.11mm Discharge cut-off voltage: 3.0V Voltage: 3.7V Full Charge voltage: 4.2V Temperature range: -20 +60 ºC Monthly Self-discharge rate: 0.5% Discharge Temperature Range: -20 +60 ºC Safety notes: Do not over-discharge or overcharge the battery. Doing so will shorten the batterys life and is dangerous. Please do not short circuit or it will release massive current. Do not play with fire! Do not dispose any kind of battery in or near any fire. Do not stack more than one battery.