7 CFR §51.684

The requirements for this grade are the same as for U.S. No. 1 except that all fruit must show some discoloration and at least 10 percent, by count, of the fruit shall have more than one-third of their surface, in the aggregate, affected by discoloration. The predominating discoloration on these fruits shall be of rust mite type. For tolerances see § 51.689.