The Filtech Foam Air Filter with a 90-63mm rubber neck, and the Filtech Hard Outlet Foam Air Filter with a solid 76mm aluminium neck. Both are 220mm long with 360 degree airflow and multi-layer foam filtration.

The rubber neck version suits a range of pipe sizes with the reducing rings and forgives slight misalignment. The hard outlet gives a rigid, precisely sized 76mm surface for a silicone coupler and clamp, which is more secure on a boosted or heavily vibrating install and will not distort when clamped.

Foam traps a high volume of dirt through its depth rather than just at the surface, which suits dusty and off-road conditions where a paper element clogs quickly. It is also washable and reusable, so it is serviced rather than replaced. The trade-off is that it needs oiling correctly.

Wash the foam in warm soapy water or a dedicated filter cleaner, rinse thoroughly and let it dry completely - never refit a damp filter. Then re-oil evenly with proper foam filter oil until the foam is uniformly coloured, without over-saturating it.

No. Engine oil is too thin, drains out of the foam and can be drawn into the intake, where it will contaminate a MAF sensor. Use proper foam filter oil, which is formulated to stay in the foam and trap fine particles.

It depends entirely on conditions - dusty, off-road or agricultural use needs far more frequent attention than road use. Inspect regularly and clean when visibly loaded. A clogged foam filter costs you more airflow than a dirty paper one, so do not let it go too long.