Miele's HEPA AirClean filters meet Europe's stringent HEPA 13 standards, capturing over 99.95% of all particles, down to 0.1 microns. Once activated, a TimeStrip® releases a red line of liquid over the course of one year, reminding users when it's time to replace their filter.For S300-S899, S2000-S2999, & S7000-S7999 vacuums.