1.Capacity: 250mAh 2.Voltage: 3.7V 3.Chemistry: Lithium-Polymer Technical DetailsCapacity: 250mAh Voltage: 3.7V Chemistry: Lithium-Polymer (Li-Poly) For Plantronics CS50, CS55, CS60 Replaces Plantronics-64327-01, 64399-01, 65358-01, PL6439901, RB612158Shipping Weight: 8 ounces Hitech - Replacement Cordless Phone Battery