Cross-linked polyethylene ViegaPEX Barrier tubing is manufactured to ASTM F876 and F877 standards. Recommended for use in floor heating/cooling, snow melting, baseboard and radiator connections. Outside PE layer protects oxygen barrier. Black with one red stripe for easy identification. Listed to NSF/ANSI Standards 14 and 61. For use with Viega's press and connection fittings only.