The Croc-Snap is a revolutionary product designed to simplify the process of boarding up inspection holes in concrete block walls. With a Croc-Snap and installation tool you're ready to go, no need for nail guns, leads, lead stands or circular saws. Made of 100% virgin nylon to strict tolerances, the Croc-Snap is corrosion resistant, so it will not deteriorate, nor cause run-stain spots on finishes. Nothing is simpler, easier or more effective than the Croc-Snap.