SubOhmCells Specifications: Nominal Capacity: 2800mAh Nominal Voltage: 3.7V Full charge Voltage: 4.2V Operating Temperature (cell surface): Charge 0 ~ 50 C , Discharge -20 ~ 75 C Diameter : 18.3 + 0.2/-0.3 mm ( Max. 18.5 mm ) Height : 65.0 ± 0.2 mm ( Max. 65.2 mm ) Weight Max. 48.0 g Positive terminal: Flat top Important: Never completely discharge li-ion battery ( below 2.5V under load ). Charge fully to 4.2V before first use. Never attach any metal moving part to the top-positive, or the bottom-negative battery contact. Never use force to install (insert) li-ion battery. Do not use old and new battery cells together. Use only high quality battery charger. Do not expose to heat. Do not short (connect) positive (top), and negative (bottom) battery terminals (contacts). Keep battery that is not in use in plastic holder (or any insulating [plastic] container). Do not charge unattended. Do not store your li-ion batteries fully charged (for extended period of time). Store in cold and dry place at approximately 3.7V (storage charge). After battery is discharged-don’t leave it discharged=>charge it as soon as possible.