SPECIAL ORDER ITEM. Review Returns Policy before purchase. The QCR Series collection provides essential components for secure plumbing connections in both residential and commercial environments. These annealed copper crimp rings are engineered to create reliable seals when securing tubing to brass fittings, ensuring system integrity in hot and cold water applications. Designed for longevity and durability, these rings are compatible with SDR9 tubing, making them a versatile choice for professional plumbing installations and radiant heating systems. Their robust construction supports consistent performance across various building types, including multi-family residential, educational facilities, and healthcare centers.