All glass contains a certain percentage of iron that makes up the product composition. Iron reduces the true clarity and adds a slight greenish hue to the finished product, worsening as the glass becomes thicker. Because in certain situations maximum clarity is desired, Manko can provide low-iron UltraClear™ by Guardian or Starphire® glass by Vitro. Low-iron glass contains less than 10 percent of the iron present in conventional glass, allowing more light to pass through and provide an ultra-clear view. Typical applications for this product include, but are not limited to, interior glass, shower enclosures, handrails, and certain insulated unit applications.
https://www.guardianglass.com/GuardianGlass/glassproducts/UltraClear/index.htm http://www.vitroglazings.com/en-US/Glass/Architectural-Glasses/Starphire-Glass.aspx
