Our portable belts are manufactured with Sait’s premium AOX for woodworking and their 2AH for metalworking. We believe to make a consistent airfile belt, you need to start with a good backing. This is critical due to the fact that the joints may only be a ½” wide or narrower. In using the 2AH, KT62Kand KAF products, we are using products with either an Egyptian cotton backing or a 100% polyester backing. This enables us to maintain proper joint adhesion.