The tube body is made of imported high quality 304 stainless steel spiral corrugated pipe, developed and manufactured according to Canadian CSA standards, with necked ports and flared seals, without other sealing materials. Products through the CSA certification, has been with a number of domestic oven manufacturers supporting, exported to the United States, Australia, Europe and other places. Because of its special sealing method a metal hard seal, no rubber gasket aging problems, and heat-resistant, fire-resistant, once and for all, is the emerging products to eliminate the seal ring.