In a video, Geometry and Vectors showcase their GHK Airsoft MK18 HPA system, operating at 300psi. This custom build features a GHK MK18 base, upgraded with a Samoon 7075 forged receiver, an ArtArms 140% reinforced buffer spring, an RNL improved hammer, a 202g RNL stainless steel buffer, an RNL mil-spec buffer retainer, and an EAR enhanced auto sear, all complemented by a RA-Tech SAI steel bolt carrier and the original nozzle.