Advantages of TF1 battery Metal part replaceable-Conventional metal part & variable voltage metal part for your choose. Safety- the 14500 battery inside can be took out for being charged. It has battery-reverse protection, short-circuit protection, over-charge, over-discharge protection. Cost-effectiveness- since battery can be took out, you only need to replace the body or the battery when it broke. Wideapplicationrange- the eGo-RS battery is with ego thread. So it can work with most of the atomizers in the market. Such as ce4 clearomizer, THOR CE4 clearomizers, evod clearomzier and MT3 clearomizer etc. Do you have interest in it?