KOOL-ROD is a closed cell, polyethylene, flexible, rope-like foam joint backing material.This material is virtually non-absorbent and chemically inert to most solvents. KOOL-ROD will not stain or adhere to sealant materials. It is fully compatible with acrylic, butyl, polyurethane, polysulfide, silicone, and most other cold-applied sealant compounds.KOOL-ROD is specifically designed as a compressible backing material to be used in conjunction with a wide variety of cold-applied joint sealants.