The Vector 18350 is a mechanical tube mod. Its made from C360 brass and SS304, with a heavy duty beryllium copper spring. The mod is a hybrid so it must be used with a rebuildable atomizer that has a protruding 510 pin. NOT FOR USE WITH SUBOHM TANKS. In stock form, the mod is designed for a 22mm atomizer. A 20mm hybrid head is available in limited quantities.