Audiovox BTE-9900B Battery by Amstron is designed for use with Audiovox CDM-9900, CDM-9950, and Toshiba VM-4050 cell phone models. Amstron cell phone batteries are precision-engineered and rigorously tested for voltage, capacity, compatibility, and safety to exceed original equipment manufacturer specifications. • Chemistry: Li-Ion • Ratings 3.7 Volts 1000mAh Capacity • Warranty: 4 Years