Breather filter

[koko64]

What is the part no for the little K&N filter people fit on the oil seperator box of a carbed Monster?

I have searched the K&N site and come up with a few parts nos, but not sure which one fits best and gives good venting area. RU 3230, RU 3630 are what I came up with. There were specific crankcase vent models also, but I dont know if they are constructed differently as in direction of flow (vent Vs intake), if there is a difference at all.

Thanks.

[IowaDuc]

I have 1 for sale that is for the monster sold through tpo.  pm me if interested