CGS Type 1 12g Co2Description The CGS from PolarStar is a great solution for those interested in obtaining HPA system for their AR 15 style replica but they held back because of the additional tank and air line. CGS gives the user the performance advantage of a HPA in a compact system without additional restrictions or clumsiness. It shows great results when combined with PolarStar cylinder conversion kits such as the F2, F1 or JACK, but it is compatible also with