Full CNC machined with Stainless Steel material. .45 & .40 marking engraved on the side of Barrel. The inter threaded design is compatible with M11 threaded adapter (Also our A01 Silencer Adapter). Spiral fluted to reduce the weight of the barrel as well as give it an aggressive look. It is designed for Hi-Capa 5.1 and there are 3 colours option: Polished Silver, Titanium Black and Titanium Gold.