This is a 38mm standard flow Sponge air filter comprised of 2 layers of sponge with differing porosity. The outer sponge layer is most porous and is both removable and washable. The inner layer is comprised of a denser sponge for optimal filtration VS air flow. The intake tube (connecting hose) is angled. This air filter has a total length of 11cm. The filter has a diameter of 9.5cm and length of 7.5cm.