HQRP Battery Kit for Sportdog SAC54-13735 FieldTrainer 425, 425S, SD-425, SD-425S, SR-225, SR-225S Field-Trainer Remote Controlled Dog Training Collar Receiver Transmitter SAC54-13734 + Coaster HQRP&reg; Rechargeable Transmitter and Collar Batteries Replacement plus Screwdriver and HQRP&reg; Coaster; Collar Battery Voltage: 3.7V; Capacity: 160 mAh; Li-Pol; Transmitter Battery Voltage: 3.7V; Capacity: 200 mAh; Li-Pol; 200 Days warranty!