SPI standard refers to the polishing type standard of molded plastic products developed by SPI (Society of the Plastics Industry). SPI has designated 12 grades of finishes in 4 categories, ranging from shiny to matte. Each grade has different requirements for the perfect allowable tolerance, lower numbers allow smaller deviations, and higher numbers allow larger deviations. The following list shows all finishes specified by SPI. If you want to get detailed pictures or samples, please contact us.