20′ coils. 99% pure copper. Annealed for ready bending. O.D. measurements apply to refrigerator tubing. Available in 1/4″ and 3/8″ x 20′ coils. 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.