This breather kit for all the 05+ rear wheel drive Nissan trucks (and 04+ Titans) . This simple kit allows your rear axle to breath a bit easier helping to prevent blowing axle seals. This kit will also keep water from entering the housing when crossing a stream. The kit simply consists of a properly threaded barbed brass fitting, Almost 5 feet of compliant real butyl rubber hose (stays compliant in cold and wont crack), a real K&N lifetime cloth oil-impregnated filter that can be washed and cleaned over and over (hence the kinda high price), 2 stainless hose clamps, and a few zip ties. you can certainly get creative and mount the filter where ever you'd like, but the higher up the better...there is enough hose to run the filter behind the taillight on the Xterra and Frontier with some creative routing. There are some kits on the market that use a cheapo fuel filter in the middle of the hose....those filters actually cause moisture to condense in the hose...excatly what you dont what to happen. Also, be sure the hose stays clear of the exhaust pipe when the suspension compresses. Install is about as easy as 1-2-3.....you just unthread the factory cap/plug and thread the new fitting in...really no need for teflon as there is no pressure to speak of. Plug the hose ends on and route how you want. The fitting needs to be no tighter than necessary.