These adapters are KF-50 to 1 1/2 inch NPT-male. The flange size follows ISO-KF standards and is NW-50. They are commonly used to make connections between ISO-KF fittings and 1.5 inch NPT-female fittings. The ISO-KF flanges are often called quick flange fittings because they are quick to assemble. A circumferential clamp and centering ring form the vacuum seal between the connecting flanges (please see top right figure - click to enlarge). The centering ring contains a rubber elastomer o-ring. The standard sizes for quick flange fittings are KF-10, KF-16, KF-25, KF-40, and KF-50 with flange sizes NW-10, NW-16, NW-25, NW-40, and NW-50, respectively. They are made of Stainless Steel.

Adapter KF-50 to 1 1/2 in. NPT-Male, ISO-KF Flange Size NW-50, Stainless Steel
Flange Size: ISO-KF NW-50
Pipe Thread NPT: 1.50 in. NPT-Male

Common Dimensions:

A = 2.95 inch (75mm)
B = 1.92 inch (49mm)
C = 1.60 inch (41mm)
D = 2.0 inch (50.8mm)