BMC Super Quad Air Filter - FM462/08 FM462/08Established through their success in the worlds most prestigious competitions, BMC air filters are today renowned for setting a benchmark in terms of performance, reliability and manufacturing quality. The characteristics of a cotton filter can be summarised simply: permeability, filtration, retention, re use Permeability: presents minimal obstacles for maximum air flow Filtration: prevents foreign bodies from penetrating Retention: retains solid