100 ea adhesive electrode washers, 8 mm id x 22 mm od. Washers (collars/discs) are made with 3M hypoallergenic medical tape. These double sided adhesive discs allow firm placement of reusable electrodes or other medical devices to the skin. Washers are mounted on strips. A paper lining protects the washer's adhesive. The blue tab facilitates removal. Easy and secure application to the skin. The inside diameter (ID) should closely match the electrode sensor or device diameter.