The Kangertech T3S Clearomizer is a bottom coil clearomizer tank.IT IS NOT A 510 THREADING TANK . The clearomizer comes with a 2.2 ohm bottom coil. WE DO NOT CARRY REPLACEMENT COILS FOR THIS CLEAROMIZER. These are sold as disposables meaning that once the coil is burnt you will replace the tank with a new one. The coil that comes with the T3S is a 2.2ohm coil rated between 3.5-3.8v. If you like the MTL hit of a classic style clearomizer than this is the one for you!