Rustikal grade - very diversified wood colour and structure, strong tints, healthy knots up to 35 mm in diameter acceptable, sapwood unacceptable. In engineered floorboards small losses after knots up to 10 mm in diameter are permitted.
The above image shows solid oak floorboards with a smooth surface, finished with a colourless oil (finishing code S01), dimensions of 20.5 x 140 x 610-2610 mm.