This insert allows you to configure your Modular Chest Rig to carry your type of magazine. Choose between AR, SMG & DMR to have the right fit and choose between three different colors to ensure it corresponds to your kit. For AK mags, the DMR insert is the way to go. A single AR & DMR insert has a capacity of 3 magazines while the SMG insert can fit 5 mags. The chestrig is intended to have 2 inserts inside so make sure to pick two! Check out the measurements & compatibility.