*improved sks's. The top button side folder stock increases the lop a good 2 inches. Unless you are a 5'4" Chinese soldier or a Russian with a big coat, the lop of a standard SKS is gonna be way too short. The top button stock fixes that and is the perfect balance of being light and handy. It's just light enough to leave a bruise through a T-shirt by not so light that you can't shoot a few thousand rounds in a sitting. If you are of average height then holding the pistol grip with your arm relaxed at your side should have the tip of the barrel a half inch away from the ground. Why is that important? It's not, but you will know what Cinderella felt like when the slipper fit her like a glove. For a national average 5'8" American, the top button stock fixes everything wrong with the rifle. Wrap a wash rag around the butt pad and you can shoot forever without ever stopping. It's perfection, unlike almost every other folding stock which ends up feeling cheap, wobbly and janky.