120.Msa: water hammer arrestor Ending: male threaded bspt, npt Size: 1/2, 3/4, 1", 11/2, 2", 21/2, 3" 164.Fmsa: companion flange ahmmer arrestor Ending: flange end Size: 21/2, 3", 4", 5", 6" Material: astm b-88, bronze Working pressure: 35 to 250 p.S.I.G.