For the Synergy S40P model, this filter set traps dust and dander particles with a thick pleated HEPA media filter, and captures odors with a granulated charcoal filter. It also protects the motor with a direct air motor filter. This filter set will fit the Synergy S40 Premium. For X9 and G9 models, see part numbers SF9UG-1, SF9G-1, SF9U-1, and SF9-1 instead.