Always purchase your batteries from a reputable distributor or company. Keep your stored "spare batteries" in a protective "plastic" case away from children and pets. Inspect the outer "plastic" battery wraps or "shrink wrap" around the metal battery casings periodically for signs of damage and replace the battery wrap when needed. Battery wraps are extremely inexpensive and can be easily obtained online and/or in some local vape shops. Use the correct charge adapter that was supplied with the device or a properly designed exterior charger when charging "removable" individual battery cells. Charge your device or cells on a level non-flammable surface. Never charge your device or cells in an "unoccupied" situation or when you are sleeping. Turn off your device when it is not in use, such as when carrying it in your pocket or purse. When using a multi-cell device use identical battery cells, charge and discharge the same set together, this is sometimes called "pairing" or "mating" them. Check the interior of your mod when changing your batteries or installing a new coil build for metal debris, shavings, wire clippings, foil etc... Magnetic doors that are on some "Mods" can attract said debris, this can short out the batteries causing them to "vent" and could lead to damage to your device or person, make sure you are using properly sized and properly rated batteries for the device and the coil build you intend on using. NEVER CARRY LOOSE UNCASED BATTERY CELLS IN YOUR POCKET OR ON YOUR PERSON! If you experience a device getting warmer than normal immediately turn the device off and if possible remove the cells and inspect the device, batteries, atomizer, and coil build for signs of damage or misuse. If the problem persists... DO NOT CONTINUE TO USE THE DEVICE. When disposing of battery cells check with your local authorities for proper disposal. Vape happy! and vape safe.