Brand new OEM high quality lithium-ion battery. Model: SNN5771 BT50 Battery Type - Lithium Ion cell delivers the most power per ounce and can be recharged hundreds of times with no lost of performance from "memory effect". Advanced lithium ion technology makes it possible. Operation Time - All talk and standby times are approximate. Battery performance depends on network configuration, signal strength, operating temperature, features selected, and voice, data and other application usage pattern.