Each package contains 3 pairs of closed sleeves. It is available in large size and can be adapted to fit most ears and hearing needs. They are easy to replace on the hearing aids and can be adapted to fit most ears and hearing needs. The vented sleeve design allows more sounds through the OTC Hearing Aid which helps reduce the uncomfortable feeling of plugged ears. The Sony CRE-S2VL Vented Sleeve for C20 OTC Hearing Aid provides balanced sound quality supporting the performance of the C20 OTC hearing aids.