the paragon mod copper tube with black carbon finish It comes with a single seamless 18650 battery tube. This allows the mod to have less voltage drop than a tube with extensions because the tubes do not have any additional threading beyond what is necessary. The top cap has a telescopic silver plated contact pin that will allow you to adjust to fit any length atomizer as well as adjust for any battery rattle. The 510 connector will fit any 510 threaded atomizers. The mod is 22mm in diameter & will sit flush with any 22mm atomizers. The locking ring is reverse threaded & is recessed so that it will not fire when standing up either locked or unlocked. The switch is bottom firing & spring loaded. The throw is smooth & perfect.