HQRP TWO Headset Batteries compatible with Plantronics CS351 / CS-351, CS351N / CS-351N, CS351V / CS-351V, CS361 / CS-361, CS361N / CS-361N plus Coaster HQRP&reg; TWO Rechargeable Batteries plus HQRP&reg; Coaster; Battery Voltage: 3.7V; Capacity: 250 mAh; Li-Pol; 200 Days warranty!