CMMG's Lower Parts Kit for the Mk3 contains 4 color-coded bags with parts separated into them. The clear bag contains the .308 takedown pin, .308 receiver pivot pin, two takedown pin detents and two takedown pin detent springs. The yellow bag contains the bolt catch, bolt catch plunger, bolt catch screw, bolt catch spring, buffer retainer and buffer retainer spring. The red bag contains two hammer and trigger pins, hammer spring, trigger spring, disconnect and disconnect spring. The blue bag contains the magazine catch, magazine catch spring, and magazine release button. The green bag contains the safety selector, selector detent, selector detent spring, lock washer and pistol grip screw. Also included are the hammer, trigger and pistol grip.