Your engine creates blow-by vapors that end up in an engine's crankcase that contain moisture as well as combustion byproducts and unburned fuel vapors.
The crankcase is sealed to prevent the escape of these gases into the atmosphere, but the vapors must be removed to prevent oil contamination, which will eventually lead to sludge formation.
The positive crankcase ventilation (PCV) system siphons these vapors from the crankcase and routes them into the intake manifold so they can be burned in the engine.
The PCV Valve can get clogged over time and maintenance is recommended every 50,000 miles or so.
Kit includes:
"T" shaped breather hose
Plastic Breather Tube
Breather / PCV valve
O-Ring
C-Clip
Hose Clamps