HHIP 5mm (1.969") Anvil Diameter Ball Attachment for Micrometers Includes 2 sleeves and 2 balls. Used for measuring parts with rounded surfaces. Ensure your micrometer is compatible with a ball attachment. Clean the measuring surfaces of the micrometer and the object to be measured. Attach the micrometer ball attachment onto the spindle firmly. Position the object between the anvil and the micrometer ball. Gently close the micrometer until the ball makes contact with the object. Read and record the measurement displayed on the micrometer scale. Repeat the measurement if necessary for accuracy. Release the pressure, remove the object, and clean the micrometer