Prime Grade is known to be the highest grade of wood flooring and has a very uniformed look. It is sometimes called AB-high grade. The fact that it is cut from the centre of the log makes it uniform in appearance and has very few knots. Prime grade engineered wood flooring tends to be small and unobtrusive when the quality of wood grade does contain knots and when the sap content of the wood is low. One of the most common considerations for choosing a wood grade is the colour variation, this is minimal, but still there, because wood is a natural product.