The Sig Sauer MCX Rattler features a short 5.5" barrel and a side folding arm brace. The new PCB brace fits the contour of your shoulder by shifting right or left. The gas asjusment allows you to tune the piston block to the exact ammunition that you want. All of the controls are set up very similarly to what you would find on an AR-15. All of the necessary controls are ambidextrous and positioned perfectly. This pistol makes for a very compact firearm especially when the brace is folded to the side. You can attach your choice of QD sling to the hand guard and lower receiver. M-Lok cuts in the fore end allow you to attach just about anything that you could ever need to. If you are looking for a great PDW, you need look no further!