R-20 Tooth Bleaching Shade GuideTeeth Whitening Shade Guide (R 20) Shade guides are used to determine the starting and finishing shade for tooth bleaching services. It is very important to use a bleaching shade guide when whitening, not a standard restoration shade guide, as bleaching tones are different. Product Code: #512 001Unit Type: 1 unitUse: Chair side & In Office Only (Professional Clinical Use) Fern Whitening Supplies is the only supplier that offers the standard R 20