The smallest breather in our catch tank range at 40mm across and 40mm tall, this filter vents crankcase and catch tank pressure without letting oil mist spray over the engine bay. Its short body suits builds where bonnet clearance is marginal, or where the tank sits low against the inner guard and a taller filter simply will not fit. Typical uses include small-capacity catch cans, rocker cover breathers and dry sump tank vents on street-driven turbo and naturally aspirated engines. The element can be removed and cleaned as part of routine servicing, so it is a fit-and-forget item once the plumbing is sorted.