These domes and tubes are for use with the Oticon range of micro BTE and RITE aids. These consumable items are supplied as Oticon ‘like for like’ replacements. You should be able to identify the exact product you need by careful examination of the slimtube. Oticon tubes have the sze etched in red near the point where it attaches to the dome. If you get stuck, email us and we will try to help you.