Koolance SPR-13BK Tubing Spring Wrap, Steel Black for OD 16mm (5/8in) Tubing outer spring to help avoid kinks in tight areas. Steel with black plastic coating. For 16mm (5/8in) external diameter tubing. Spring length can be compressed or stretched while on tubing for segments 6-32" (15.2-81.3cm) long. Trim with wire cutters for shorter lengths, or stack multiple pieces for more coverage.