https://tefcopiping.com.au/product-category/poly-fittings/backing-rings/
Backing Rings - Tefco
backing rings
https://www.imperialweldringcorp.com/index.html
Weld Backing Rings | Consumable Weld Inserts | Weld Test Coupons - Imperial Weld Ring Corp.,...
Imperial Weld Ring Corp., provides metallic welding products including weld backing rings, precision machined rings and fittings, consumable weld inserts and...
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