Closed Sleeve for the Sony CRE-C20 Self-Fitting OTC Hearing Aid Each package contains 3 pairs of closed sleeves. Sleeves available in four sizes to account for different size ear canals: XS, S, M, and L Can be adapted to fit most ears and hearing needs. These sleeves are not compatible with CRE-C10 and CRE-E10 OTCHA models. These sleeves are included in the CRE-C20 product kit.