Feature:1. 312 BATTERY: The rechargeable unit can be used with a variety of hearing amplifier devices that use 312 batteries and generally lasts 710 hours for nonBluetooth hearing aids and 36 hours for Bluetooth hearing aids.2. CYCLIC CHARGING: Button battery charging case can be charged and cycled, equipped with a USB charging cable, you can charge it at any time.3. TWO BATTERIES: Contains two batteries to ensure that your hearing amplifier is charged at all times and can be purchased with confidence.4. PORTABLE DESGIN: Small and light enough to take with you anywhere, whether you are traveling for business or pleasure or on the go, you can always power your hearing amplifier.5. LONG LASTING: Contains 2pcs 312 button batteries with 155mAh capacity, ready to power up your hearing amplifier device.Specification:Item Type: Hearing Amplifier Batteries ChargerProduct Material: ABSProduct Use: can be applied to a variety of hearing amplifier using 312 batteries, for non-Bluetooth hearing aids, they typically last 7-10 hours; for Bluetooth hearing aids they typically last 3-6 hoursMatching Batteries: 2 x 312 batteries (built in)Battery Capacity: 2 x 155mAh.Package List:1 x Charging Box1 x USB Charger2 x Button Battery