HPFlex is a Universal Urethane. Flex Additive is designed to increase flexibility, impact resistance and chip resistance. HPFlex mixes easily and does not affect dry or cure times. Mix 1-2 ounces per every 32 ounces of paint. Universal Urethane Flex Additive is not recommended for use with non-urethane products. When using All Tamco urethane products, remember you have a inherited built in "flex additive" in the products. They are inherently more flexible than the average products on the market due to the resins we choose to Use. In most cases, flex isn't required with the use of Tamco. This is universal and can be used in any other brand.