Kuranda heavy duty dog beds utilize our chewproof bed frames in combination with 40 oz solid vinyl, the most durable material we have found in 18 years of making dog beds. Our heavy duty beds were developed to stand up to daily use in kennels and shelters and thus are an excellent choice for very active, rambunctious dogs. We insert an aluminum tube into each side of the poly resin frame of our larger beds to keep them from sagging under heavy weight.