Protect battery column and battery pile head, and prevent corrosion. Applicable battery type: Suitable for batteries with battery columns at the top and side of the battery. Type: BC2127. Dimension: outside diameter: 45mm/1.8in, inside diameter: 18mm/0.7in. Note: Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Please allow 1-2cm measuring deviation due to manual measurement.