99% pure copper. Annealed for ready bending. O.D. measurements apply to refrigerator tubing. Mueller Industries dehydrated refrigeration coils are made to ASTM standard B-280. The copper tube is cleaned, nitrogen urged, capped (with standard yellow caps) and shrink-wrapped to an air tight seal.
WARNING: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer. For more information, go to www.P65Warnings.ca.gov.