SL-300 Professional Windscreen Sealant is a black, non-hardening synthetic butyl rubber based sealant. It is a sticky ribbon type auto glass replacement sealer used for the installation of all gasketless windshields and backlites. SL300 offers a fast and clean method for installing the glass instantly with superior adhesion. The sealer has excellent compressibility in both low/high temperatures. It is designed to maintain position, permanently sealing and waterproofing between the glass and pinch weld.