In the Box 1x ABS Polymer Upper Receiver1x ABS Upper Receiver Mock Bolt Retaining Plate1x ABS Front Sight- 1x ABS SRC STRYKE Series Two Piece Hop Up Chamber1x Inner Barrel Retaining Clip1x 5 in. ABS Barrel Extension1x 2 in. Barrel Extension Specifications: Construction ABS PlasticCompatibility SRC STRYKE Series M4 AEGsColor BLACK California Proposition 65 Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov