Ordering Description Product number Description: Tweco Pulse Master-55 Series Gas Diffuser, Brass, 16PS, 5 Per Pkg Product number: 1550-1105 Description: Tweco 55S-SWL Gas Diffuser, Copper Product number: 1550-1120 Description: Tweco 55S-H Gas Diffuser, Copper Product number: 1550-1111 Description: Tweco 55S-SW Gas Diffuser, Copper Product number: 1550-1110 Description: Tweco 55H Gas Diffuser, Copper Product number: 1550-1102 Description: Tweco 55SW Gas Diffuser, Copper Product number: 1550-1101 Description: Tweco 55 Gas Diffuser, Copper Product number: 1550-1100