Replacement battery fits 12 Spring compatible models. Specifications: 2000mAh, 12V, Ni-MH. Compatible with: EDANINS ECG-1A, ECG-901B, Biomedical ECG-1A, Biomedical ECG-2201, Biomedical ECG-2201G, Biomedical ECG-220 and 6 more compatible models. Replaces: Eton HYHB-1172, Biomedical HYHB-1172. Spring replacement battery designed for Medical devices. Designed for long-lasting power.