DIE FREE CO. DOS BOOT MAGAZINE EXTENSIONS FOR PMAGA(R) GEN M3 AR-15 MAGAZINE Introducing the Dos Boot(TM) by DFCO(TM) - an enhanced base plate upgrade for your Magpul PMAG GEN M3 AR15/M4 magazines. The Dos Boot adds +2 rounds of capacity, converts your PMAG into a convenient monopod, and improves grip for quicker, smoother reloads. It's the unintrusive and practical magazine upgrade you deserve. Die Free Co. designed the Dos Boot with 20-round mags in mind, aiming to get as low to the ground as possible without letting your rifle grip touch dirt. The result? A sleek extension that gives you a 10% capacity bump, better stability in prone, and Mfg: Die Free Co