iMah Ryme B31 Rechargeable Headset Battery Compatible with Plantronics CS50 CS55 65358-01 Battery (2-Pack) Specification: Replace Model: 65358-01Voltage: 3.7V Capacity: 190mAhWeight: 5.1g / 0.18oz per battery pack Type: Lithium-Polymer Rechargeable: Yes Dimension: 33 x 20 x 3 mm / 1.3 x 0.79 x 0.12 inch Compatible with the following Plantronics Headsets Models: Plantronics CS50 Wireless Headset SystemPlantronics CS50 BatteryPlantronics CS55 Wireless Headset SystemPlantronics CS55 Battery Replace of the Original Battery Part Number: Plantronics 65358-01 batteryPlantronics 64399-01 battery Specification: Voltage: 3.7V Capacity: 190mAh Weight: 5.1g / 0.18oz per battery pack Type: Lithium-Polymer Rechargeable: Yes Dimension: 33 x 20 x 3 mm / 1.3 x 0.79 x 0.12 inch Please kindly check the compatible lists to make sure the right replacement You can also compare the battery Cell Size & Connector Type with your original old battery pack All the iMah Batteries comply CE, RoHS, MSDS, UN38.3 certifications.Built-in lithium battery charge and discharge protection chip, will provide a safety work platform for ears.Designed to meet or exceed performance of original battery.Tested by manufacturer to match the OEM products.