02. The Currie Track 9 housing was originally designed for the NASCAR guys. The idea was that they could pull the rear cover for a quick inspection instead of having to pull the axles and third member. NASCAR eventually outlawed it since they felt the cover was another spot where a car could leak fluid onto the track if the crew was in a hurry and forgot to use sealant. It's a great piece for the guy who wants the benefits of a 9-inch without it being glaringly obvious.