Sturdy aluminium frame with bonded filter pack, protective grills and neoprene gasket.  Our HEPA filters conform to the requirements of BS EN1822:2008 and are tested in accordance with PD6609, with certified efficiency of 99.995% @ 0.3 micron.  The filters come with a mounting spring kit to ensure that the neoprene gasket seals without fail.  ** FOR USE WITH SA640, SA1000, AS300 AND GP540 ENCLOSURES**