[Features] ● Easy and quick welding installation is possible. ●The tension spring supports the ring at the desired position and reduces noise. (1, 5t to 10t) ●Compliant with DIN5688, quality grades 100 and 80, and 100% passed magnetic testing. ●The spacer (approximately 3 mm) functions as a gap material required for root welding. ●DIN18800 requirement can be established by arrangement of weld seams (HV penetrating type). This means that the seams are completely shielded and can be used outdoors without the risk of forming a corrosive layer.