Grademark.

A grademark normally consists of three symbols which indicate group, quality, and color. A letter is used to indicate group, a number to indicate quality, and a letter or letters to indicate color. For example, B3F means Leaf, good quality, orange color. [42 FR 21092, Apr. 25, 1977. Redesignated at 51 FR 25027, July 10, 1986]