AS Performance Engine Oil Breather system with oil level indicator & full fitting kitAS Performance brings you this great addition to your ST150, After taking our own Supercharged ST to 300+bhp we noticed on fast road and track use we was seeing oil coming from the crank case breather, we have also seen this in re mapped normally aspirated ST's as well. Commonly known as an Oil breather, this neat kit actually separates the oil were it would cause excess smoke from getting thrown into the inlet manifold from the crank case breather,