Nominal Voltage: 3.7v Battery Model: 26650 Capacity: 3500mAh Positive: Flat top Cycle Life: 500 Cycles Max Charging Rate: 4.5amps General information on battery safety: Do not overcharge or over-discharge batteries. Do not leave your batteries on the charger unattended. It is a good idea to check on the charger every 15-30 minutes. Do not charge batteries over 4.25 volts as it may reduce its lifespan. Charging over 4.5 volts can also cause the battery to burst. When purchasing a charger, ensure that it has safety features built in to prevent overcharging. Recharge batteries that have dropped below 3.6V and try not to over drain them. If the battery is drained below 3.6 volts it may never recharge fully. Do not short circuit your batteries. Shorting ANY battery can potentially burn it out or cause it to explode. Keep in mind that batteries have unique amp drain limits as indicated on the product pages. Building coils with low resistance may push the battery past its amp drain limit which can cause thermal overload. If you are building your own coils, a working knowledge of Ohm's Law is essential. Do not let your batteries touch metallic items. When carrying spare batteries, make sure to keep them in an insulated case. Loose change and other metallic items can create a path between the positive and negative contacts. Lastly, always ensure your batteries and battery wraps are in good working condition. For customers at our local vape shops, we provide free re-wrap services. Batteries with dents, or that are leaking fluid are not considered safe and should not be used.