26mm straight to battery 510 copper tube with a Rogue Mod style switch minus the polycarbon Spring. Design cues have been taken from the Rogue on the size/dimensions, shape, bevelling and switch. I was in the market for a copper Rogue, but chose on impulse to go with the Crossbones as it is slightly thicker and heavier and came paired with a rather interesting rda, the Unholy. Which has a 2 post clamp system, small chamber, nice size juice well and a very interesting side AFC.