All in One Kits which is known as AIO Kits are devices which tend not have any separate parts and the whole device is usually encased within an outer shell. With an AIO device, you will receive everything you will need to start vaping. This includes the device, charger and replacement atomizer heads. The AIO style of kit makes vaping simple and very easy. If you are every in doubt, an AIO kit is the best way forward.