Less than 1% sapwood on face of boards, small knots (less than 1" diameter), and fillable cracks allowed on less than 10% of floor. The ½" flooring has an average length of 32" and an extra thick sandable surface while our ¾" flooring has an average length of 42" and an extra thick sandable surface. All of our Old Growth Select has Tongue and Groove milling on 4 sides.