JRENUM® Hearing Protection The individually custom fitted hearing protection device JRENUM hearing protectors have an acoustically selective filter and are individually fitted to your ear. The protection range can be adapted to the protection required for specific situations. JRENUM can be worn comfortably all day long - on the basis of exactly fitted impressions. Full protection is guaranteed; JRENUM absorbs unnecessary frequencies, damaging sound pressure levels, and makes communication in noisy environments easier.