Comparison : Item # 1031-3300-61-08-08, 1/2" Tube O.D. x 1/2" Tube O.D. Flange Steel Bore-Flange O-Ring Face Head Code 61
Item # 1031-3300-61-12-12, 3/4" Tube O.D. x 3/4" Tube O.D. Flange Steel Bore-Flange O-Ring Face Head Code 61
Item # 1031-3300-61-16-12, 1" Tube O.D. x 3/4" Tube O.D. Flange Steel Bore-Flange O-Ring Face Head Code 61
Item # 1031-3300-61-16-16, 1" Tube O.D. x 1" Tube O.D. Flange Steel Bore-Flange O-Ring Face Head Code 61
Item # 1031-3300-61-20-20, 1-1/4" Tube O.D. x 1-1/4" Tube O.D. Flange Steel Bore-Flange O-Ring Face Head Code 61