Commercial Optex with color changing technology is an ultra-premium commercial filler with extended working time that helps commercial shops work larger areas and save time and money. There's no second guessing once mixed with cream hardener, Optex changes from pink to green indicating the repair is ready to sand. Formulated with Evercoat's patented Ecoresin technology, Optex offers superior adhesion to a broad range of substrates and unparalleled sanding properties.