This is an elastic magazine carrier that slides onto a belt. It will fit most belts up to 1.75?. You can use the accessory slot to carry an extra magazine, knife, or tourniquet. The accessory slot also has the "Sticky" material to help hold smaller or smooth items in place. It is open ended so a variety of different sized items can be carried from a single stack .380 ACP magazine up to a large double stack .45 ACP magazine and everything in between.