Kidde Airsense 9-30072-P Dust Separator Cartridge (Pack of 6) HSSD MK1 Ex filter pack A pack of 6 cartridge type filters for use with all variants of the Stratos HSSD MK1 Aspirating Smoke Detection unit. NB Stratos HSSD MK1 is an obsolete product and it is advised to upgrade these detectors as soon as possible. This filter is also used inside the external stainless steel filter unit (30730). This dust separator cartridge installs in the Stratos-HSSD detector only. The cartridge is not cleanable and must be replaced when contaminated. Stratos-HSSD monitors the separator condition and will generate a separator fault when replacement is necessary.