See: BSRC

BSRC have introduced their air filter foams. Available in natural (un-oiled) or pre oiled with a specifically designed Bio filter oil. The Bio oil is biodegradable, non toxic, very tacky, but very breathable. Perfect for nitro RC racing as its fuel proof, water proof and unlocks the hidden horsepower in your engine. The air filter foams are available for the TLR style Air Filters, Mugen MBX8 and Kyosho MP9 Tki4 in packs of 10.