Replacement battery for KM500. Specifications: 2000mAh, 6V, Ni-MH. Compatible with: KM500, KM-500 Auto Keratometer, Nidek keratometer KM500, Nidek KM-500BPI. Replaces: Marco MA-3010, Marco KM-500BP1, Nidek 02904, Nidek B11304, Nidek KM-500BPI. Marco replacement battery designed for Medical devices. Built to OEM specifications for reliable performance.