Features1312 BATTERY: The rechargeable unit can be used with a variety of hearing amplifier devices that use 312 batteries and generally lasts 7?10 hours for non?Bluetooth hearing aids and 3?6 hours for Bluetooth hearing aids. 2CYCLIC CHARGING: Button battery charging case can be charged and cycled, equipped with a USB charging cable, you can charge it at any time. 3TWO BATTERIES: Contains two batteries to ensure that your hearing amplifier is charged at all times and can be purchased with confidence. 4PORTABLE 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. 5LONG LASTING: Contains 2pcs 312 button batteries with 155mAh capacity, ready to power up your hearing amplifier device.SpecificationItem 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 155mAhPackage List1 x Charging Box 1 x USB Charger 2 x Button Battery