This adapter rubber hose nozzles are KF-25 to rubber hose and fit a 10mm Iner D rubber hose. The flange size follows ISO-KF standard, They are commonly used to make connections between ISO-KF fittings and rubber vacuum hoses. The ISO-KF flanges are often called quick flange fittings because they are quick to assemble. They are made of Stainless Steel.
A=40mm / 1.6inch, B=10mm / 0.4inch, C=8mm / 0.3inch, D=40mm/ 1.6inch