2x Pack - Plantronics 65358-01 Battery - Replacement for Plantronics CS50 Headset Battery (250mAh, 3.7V, Lithium Polymer) Replacement Plantronics 65358-01 Battery Replacement for Plantronics CS50 Headset Batteries Quantity: 2, Lifetime Warranty Capacity: 250mAh, Upstart Battery Brand On Sale for a Limited Time!