There are hundreds of different types of wood and each type has different qualities. The quality of a specific type of wood is often judged on the drawing, so wood with a nice pattern in the grain is rated higher. Not all woods are suitable, some are too soft, too porous and some are even toxic. Wood must be well finished so that it is as smooth as possible. The quality of the finish varies greatly from one manufacturer to another. Know that the cheap plugs can generally be offered at a low price because they are often not made of the finest qualities of wood or because the finish is below standard.