Clear grade - A flooring product of mostly heartwood with a minimum number of character marks and discoloration, providing a uniform appearance while allowing for all heartwood natural color variations. Will admit 3/8" bright sapwood entire length of strip or equivalent if not extending further than 1" for 1/3 length of piece; small burls and fine pin worm holes; and equivalent characters such as small tight checks; in the absence of these, one thin brown streak 3" long to be allowed every 6'. Select- The face may contain unlimited sound sapwood; slight imperfections in milling; a small tight knot every 3'; pin worm holes; burls and a reasonable amount of slightly open checks. Brown streaks should not extend the entire length of a piece; two worm holes to every 8' are permitted. #1 common - May contain varying wood characteristics, such as flags, heavy streaks and checks, worm holes, knots, sticker stain and minor imperfections in working. Broken knots over ½" in diameter are not permitted. #2 common - May contain sound natural variations of the forest products and manufacturing imperfections. Antique Oak - recycled from old floors, beams, floor joists, and other formerly used construction parts. Wood full of wear marks, stress cracks, solid knots and character.