Here are some pictures of a quad ring installed on 3 different types of couplers.

First one is of an original ISO coupler on a 4440 European model

Second one is of a replacement ISO coupler on the same tractor.

Third is a JD style coupler on a 8640

Of the 3, I think that the JD style holds up the best. Next is the original. The replacement ISO is crap. Always leaks.

(quad 001 (Small).jpg)

(quad 002 (Small).jpg)

(quad 003 (Small).jpg)

(JDStyle.jpg)

(quadring.jpg)

quad 001 (Small).jpg (35KB - 342 downloads)

quad 002 (Small).jpg (41KB - 341 downloads)

quad 003 (Small).jpg (38KB - 340 downloads)

JDStyle.jpg (83KB - 331 downloads)

quadring.jpg (33KB - 350 downloads)