Grade of Oak
Small and sound knots, up to 10 mm of diameter. No sapwood. Colour is relatively uniform.
Sound knots up to 15 mm, light sapwood, variation of colours.
Unlimited sound knots from 10mm and up to 40 mm of diameter for strips of parquet from 130 to 180 mm. No sapwood. Discolouration allowed.
Knots with unlimited and various sizes with wormhole limited. Pierced and crossed knots allowed. Cracks are limited to 50 mm in end of strip.
Wood flooring with important variation of colours and sapwood.