Oak plank in 3-layer construction with small bevel on the long side and approx. 4 mm top layer, with approx. 4 mm backing in the same wood and middle layer conifer. Tongue and groove on all sides for easy installation. Planks with healthy knots are part of the appearance as are cracks up to 30 cm, knots, and knotholes sealed with golden wood putty. Repairs up 25 mm diameter are possible. Homogeneous knot appearance. Small open cracks and unsealed spots of a few millimetres are permitted.