Zr702 tubes, 23~28mm inner diameter, 3mm thickness, black zirconium rings

Zr 702 is a zirconium grade characterized by immunity to stress corrosion cracking and high resistance to pitting and crevice corrosion. The grade has very good corrosion resistance in most organic acids, excellent corrosion resistance in mineral acids, good corrosion resistance in strong alkalis and moderate mechanical strength.
Hypo-allergenic, bio-compatible, and ultra-corrosion are just 3 of its most important characteristics. So Zr702 are often used to make rings.