Wood in the Natur grade is characterised by uniform colouring of the floor within one board and a varied grain arrangement. The Natur grade only allows small knots, of the same colour as the wood, up to 7 mm in diameter and not grouped. In this selection, the boards must not have discolouration, cracks, broken knots or sapwood, but shine, i.e. streaks and spots with a pronounced sheen, characteristic of oak wood, is allowed. However, it is important to know that even in this grade the boards within one batch may slightly differ in tone, because wood, as a natural material, absorbs pigment differently.