HQRP Battery compatible with SportDOG FieldTrainer 400S SD-400S SD400S Remote Dog Training Collar Receiver plus Coaster HQRP&reg; Rechargeable Battery plus HQRP&reg; Coaster; Battery Voltage: 4.8V; Capacity: 180 mAh; Ni-Mh; Compatible with Original Battery; 200 Days warranty!