ZZ-GRIP® OPTEX® is an advanced clog-free, lightweight body filler with patented OPTEX® color-changing technology. There's no second guessing; once mixed with cream hardener, OPTEX changes from pink to green indicating the repair is ready to sand. Formulated for superior adhesion to galvanized steel, bare steel, and aluminum. Z-GRIP® OPTEX® is a part of the METALWORKS® system that guarantee that the repair will maintain the O.E.M. corrosion warranty on original factory corrosion protected sheet metal and galvanized sheet metal when used in accordance with the application instructions.