Mike, mrcaptainbob-beat me to getting you answered. It's a poly like usually milky white plastic compound used a great deal in manufacturing. Simular to nitrile, nylatron-it is used as slide plates, chain tensioners, guides, or spacers. It machines very well and is esay to cut. If Mrs. Mike has a cutting board on the kitchen counter, it is possibly UMHW. Its soft but very tough and it won't hurt the teeth on the chain saw. Hope this helps. I use a 1/2" X 6" X 12" piece to fillet fish on, works great and doesn't harm the knife blade.