Oil catch tank help

[Trophy348]

Hi just purchased an oil catch tank and has 2 inserts for a pipe,just wondering were the other pipe goes after I have fitted one pipe to the back of the engine?
​thanks

 

[Martin.]

To a breather if the catch tank lid doesn't have one.

 

[Trophy348]

Ok so fit a filter on it? Thanks

 

[Martin.]

What catch tank do you have?