Rechargeable Hearing Aids for Seniors and Adults 24 Channel Digital Noise Case otc hearing aids power up in just 1.5 hours and deliver up to 20 hours of continuous use per chargeā€”with up to 80 hours total using the sleek, portable charging case. Features an ergonomic in-ear design made from soft, skin-friendly silicone. 5 volume levels and 2 modes (Normal / Noise Reduction). Open Box.