High quality alloy steel machine screws & washers. 8 pieces as shown. #8-32 x 1/4", #8-32 x 3/8",  #8-32 x 5/8". This is an extra parts kit. You'll probably only use one medium and one long screw plus maybe a washer. The rest are provided as backup. Dye Dam/Playable Dynamics compatible. Short screws are for the top of hand guard. Long screws go in the lower spot near magwell. Use the washers only on the long lower screw and only if necessary.