Widex CeruStop Standard Cerumen Filter (without Nano Coating), diameter 2.1 mm. In packs of 8 per box. Includes filter changing pen. Protects your hearing aid from earwax build-up and helps maintain the performance of your hearing aid. Suitable for the following hearing aids: Widex (CIC, ITE, Passion, Fusion), Oticon (hearing aids that use Micro Moulds), Phonak (Audeo Yes, Audeo Mini, Audeo Smart) and Unitron (all Moxi models), Beltone First, Legend and ReSound LiNX.