This is the one many here use:
Color/Finish: Silver Material: Metal Dimensions: Overall Length: 86.50mm Width (at widest point): 28.85mm Engine Inlet OD: 14.15mm Engine Inlet 11.85mm Filter (Air) Outlet OD: 12.00mm Filter (Air) Outlet ID: 9.45mm Fits: Universal Note: Easy Installation (Linked Below)
www.mikesxs.net
I fit mine to the hose coming off the timing case breather barb and pipe its output up to the oil tank breather connection. Helps with various pressure related seeps/weeps from places like the rocker covers etc.
If money is not a concern, there in the CNW or Holland Norton Works sump breather, which replaces the large sump drain plug on 850 engines only....hose pipe runs up to tank breather connection. These run $200-$300 USD last I checked....