Has an M130 spring and a tight bore barrel in it, and a few other upgrades. I will include the original spring to get at back under 400 fps. I don't remember exactly what all was done to it because I'm not a tech and it was a while ago lol. The buffer tube needs to be tightened, that's why the stock looks bent. It's not, it's just loose. Package Includes: • Krytac Trident SPR • CVLife 3-9X40 scope • Front and rear metal canted iron sights • VFC QRS Stock • Keymod RIS rail segment • 2 rubber keymod rail covers • Tenergy 11.1V 1000 mAh 20C battery • Original Krytac spring • 4 140 rd DMR style midcap mags • 3 High cap mags • 1 random patch from my patch wall :)