Aio stands for All In One, this means that the device is a complete unit which will only required either a replacement pod or replacement coil. A great example of an AIO Vape Kit would be the Nord 19 AIO Kit from Smok. The Smok Nord AIO 19 Kit is a 19mm pen style vape kit that uses either the 0.8 ohm Nord Mesh Coils for direct lung vapers and 1.4 ohm regular coils for a mouth to lung (MTL) style vape.