PU, or polyurethane, is a synthetic material that can be formulated in different ways to create different types of finishes, including matte, glossy, and satin. The process of applying a wooden PU finish typically involves several steps. First, the wood is cleaned and sanded to remove any rough spots or imperfections. Then, a primer or sealer is applied to the surface to create a smooth, even base for the PU finish to adhere to. Next, the PU finish is applied using a brush or spray gun, depending on the type of finish and the size of the surface being treated. Multiple coats may be required, with each layer allowed to dry completely before the next one is applied. This ensures a smooth, consistent finish with no visible brush or spray marks.