The A-Plus Open Gun, 4500PSI@12GPM (8.710-398.0) is just plain comfortable. It fits a wide variety of pressure washer makes and models. Open guns do not have a trigger meaning they do not require an unloader assembly. Because water is constantly being dispensed there is never pressure build up in the pump. Guns like this are also often used in steam applications where constant flow is necessary to avoid dangerous pressure build up.