Entropy Resins Super Sap CLS Slow Hardener (32 oz.) CLS Slow hardener, formulated for use with Entropy Resins Super Sap CLR Epoxy CLR Reference Card included to assist users with accurate mix ratios and set times relative to ambient temperature. This eco-friendly epoxy has an excellent viscosity for hand layup techniques and employs an air release package to ensure smooth coatings. Designed for colored substrate applications, added UV stability makes it ideal for epoxy clear coats and low yellowing finishes.