The replacement Diffuser for the Brevida Nasal Pillow CPAP Mask is a cap filter that attaches to the elbow of the mask and offers dual-purpose functionality: it traps fine particles and it helps diffuse the sound of air being released during sleep therapy. The Brevida Nasal Pillow CPAP Mask diffuser only works with the Brevida Nasal Pillow CPAP Mask. Find all compatible parts listed here on the Brevida Mask Parts page. General Tips Section Please Note: This is for the diffuser cap only and does not include the rest of the elbow or any other accessories required to operate the mask. Cleaning Tips: Over time, the diffuser filter and cap can become dirty and lose functionality. It can be washed, however. Wash at least once per week in warm water with mild soap. Do not exceed 10 minutes. Rinse with fresh water until all soap residue is gone and allow the components to air dry away from direct sunlight before wearing. 400BRE161