... Pressure filled glycerine 0-500 PSI, class 1.6 connection back ... connection bottom 1/8"NPT, 2-3/4"dia.RW-RG-500Red pressure ... 0-500 PSI, class 2.5 connection bottom ... 5RW-FRG-500Red pressure 0-500 PSI, connection back 1/4"SAE ... PSI, class 1.6 connection back 1/4"SAE, 2- ... PSI, class 1.6 connection back 1/4"SAE, 2- ... PSI, class 1.6 connection bottom 1/8"NPT, ... PSI, class 1.6 connection bottom 1/8"NPT, ...