``U.S. No. 1'' consists of pecans in the shell which meet the following requirements:
(a) Free from loose extraneous or foreign material.
(b) Shells are: (1) Fairly uniform in color; and,
(2) Free from damage by any cause.
(c) Kernels are: (1) Free from damage by any cause.
(d) For tolerances see Sec. 51.1404.