A small-format breather catch tank measuring 53 x 65.5mm. The compact size is the reason to choose it: many modified engine bays simply have no room for a full-size tank, and a small unit mounted where you can actually reach it is worth more than a large one you cannot fit. It performs the same job of intercepting oil-laden crankcase vapour before it reaches the intake, keeping the intercooler and throttle body clean and satisfying the catch tank requirement at most track events. The trade-off is capacity, so drain it more often, particularly if the engine breathes heavily or you run long sessions.