This fitting is compatible with several of our 300 and 400 series water pumps. WP337, WP362, WP431 and WP432 are examples of a few pump numbers where this fitting could be used. One end is #16AN o-ring boss configuration and the other end is #16AN for a standard hose end. Extra length can be helpful when 2 angled hose ends are running next to each other. This is common when used in conjunction with WP337 or WP362.