Replacement Battery For: Sennheiser HD 4.40, HD 4.50, Urbanite XL, Momentum 2.0 Wireless Bluetooth Headphones, AHB622540N01 100% Compatible with original battery; 180 days warranty Capacity: 800mAh; Nominal Voltage: 3.7V Battery Type: Li-ion Polymer battery; Safe and reliable battery certified by UL, CE, UN38.3, RoHS Over 300 times cycle life; Long working time