The battles wings turn your f1 mainframe into the perfect day pack. Lots of room for gear. Spotting scope, tripod snacks ect. And the ability to pack out game at the end. I use them in conjunction with the vapor 5000 for multiple day hunts. My only complaint is they don't have the zipper keeper on both sides. But a small zip tie fixed that. Overall very happy and recommend them to anyone looking to build a modular hunting system