SMOK D-Barrel Mod has two parallel barrels, like double barrels of a gun, where tow shots are fired in rapid succession when pulling the trigger. Besides, this kind of open design enables you to feel authentic existence of barrels. A barrel is a crucial part of gun-type ranged weapons, and so is D-Barrel, which uses 2 x 18650 battery as its power source. Innovation keeps changing the vaping experience.