Carry your batteries or your e-liquid vial or atomizer in the blue NBM40 Multi-Purpose Portable Battery Magazine from NITECORE. This compact, streamlined case will hold four 18650 lithium cells or one vial or atomizer measuring up to 0.9″ / 23mm in diameter. A touch-fastener ribbon attached to a loop on the side of the magazine wraps around the unit for extra security. By putting a chain or thread through the small ring on top, you can attach the unit to your belt. It can also be stored easily in most pockets. The magazine is made from a durable, rubber-like gum/polymer, which is flexible while providing some protection against light impact.