Dear sir / madam, we are a manufacturer of forged flanges used in engineering, chemical and wind tower industry in china. large diameter ring flange with non-standard is our advantaged products. please let me know if you buy the forged flanges or any ring flanges with large diameter for your equipment or to resell to your customers and i can send you more information regarding our products. our common products' info: max od: 2800mm, min id: 500mm, max thk: 350mm. with certificate tuv rheinland, advantaged price can be provided by using materials like sa105, c45, 42crmo4.