The KRTYAC Trident MKII M4 receivers are the chassis from which the entire gun is formed and are made from aluminum alloy to be both strong and lightweight. The KRYTAC logo and right and left selector modes are stamped on the receiver. Included with the upper and lower receiver are the body pins to keep them together. The KRYTAC Trident M4 receivers can serve as replacements for an existing KRTYAC gun or as the solid foundation for your next custom AEG build. Available in Black, FDE and FG