Genuine Boge 306 style soft tip cartomizers available in 2.0 ohm and 2.8 ohm (Black and Stainless).  306 cartomizers are 100% compatible with any  510 battery thread. These are standard length 510 35mm (Tube Length) x 8mm diame tercartomizers and will hold .8-1ml of liquid. These will NOT fit in cartomizers tanks, the diameter is to small at 8mm. These are blank cartomizers and will need to filled with e-liquid before using them. Running this without e-liquid can burn the filler inside as well as permanently  damaged the cartomizer.