These filters slot in between the Diffuser Cover and the Elbow on all Eson CPAP Masks. When in place the diffuser will lower the sound level of any Eson Series Mask by approximately 8 dB! This package includes 10 diffusers as well as a Diffuser Cover. USAGE: The Diffuser Filter and Diffuser Cover are optional items which help to make the Eson Nasal Mask extra quiet. Diffusers are not required for proper operation of the mask."
