Everything you need for your custom AR10 build, and nothing you don't. Just the basics from KAK. This kit does not include a FCG- No trigger, no hammer, no disconnect AR10 Bolt catch kit including bolt catch screwMagazine catch kitAR10 Takedown pin, detent, & springAR10 Pivot pin, detent, & springBuffer retainer pin & springSelector, detent, & spring (Reversable Selector- Left or Right side of Lower)Hammer & trigger pinsHammer, trigger, & disconnect springs