The product is a lot of 3 BT-000398 BT-000397 batteries specifically designed for the RS51 RS5100 2D Bluetooth Ring Scanner. These rechargeable batteries are of high capacity at 735mAh, with a voltage of 3.85V and a size of 42.5*29.2*17.5mm. Manufactured by a reputable manufacturer and backed by a 1-year warranty, these Li-Ion batteries are reliable and long-lasting. Perfect for keeping your scanner powered up and ready for use, these batteries are a convenient and essential accessory for your device.