85566446 is a size 3 o-ring used on the Ingersoll Rand F144I - F424I F Series Inline Filters. The o-ring sits on the filter housing and creates a sealed connection between the bottom canister and the filter head. This prevents air leaks at the housing and should be changed whenever the internal element is replaced.
Note this will only work with the below Ingersoll Rand line filters:
85565638
85565620
85565679
85565661
85565711
85565703