HQRP Battery compatible with SportDOG FieldTrainer 400 SD-400 SD400 J400-818/2, SD-350 SD350 Yard Trainer YardTrainer Remote 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!