AP Chroma Stains are universal and compatible with all major porcelain systems available in the market, including Porcelain fused to Metal, Porcelain fused to Zirconia, and Full Zirconia frames. They are suitable for both internal and external staining, allowing for the creation of even the most challenging color effects. With the AP Dental Chroma Stain shades A,B,C,D the desired chroma shade can be achieved for the "Classic" or the "Zircon" ingot.