Although the reverse face of D Select shall permit sound characteristics typical of Standard grade material, C Select shall only permit the characteristics of D Select on the back. D Select, which is the lower of the two grades, allows pin knots (maximum size is approximately 1⁄2") and limits the total number of pin knots to one knot per surface foot. Checks and shake are barely perceptible. The occasional pocket is very small. A split will not exceed 1⁄2 the width. Pitch, when present, is evident, but limited by surface area of the piece. Medium stain (blue or coffee) cannot exceed 3⁄4 of the face surface area in a clear board, and less if present with other limiting characteristics. A larger surface area is allowable if the stain is light. Skip is permissible on the back face or one edge of 20% of the pieces. Wane is limited to the back face. Occasional pieces may require a cut to yield all usable lumber for finish work (loss not to exceed approximately 5%). Characteristics in C Select are no larger and less numerous than those same characteristics in D Select.