Cameron Sino Rechargeble Battery for Fitbit Surge Type: Li-ion, Volts: 3.7V, Capacity: 100mAh / 0.37Wh Dimension: 25.75 x 15.50 x 4.75 mm, Weight: 60g All Products are Certificated with ISO9001, RoHS & CE 14 Days Money Back Guarantee and 12 Months Warranty