The Sigma-Flo coil is available in a 5/8-inch and 1-inch parallel tube pattern. The Sigma-Flo fin is designed to maximize heat transfer and minimize coil size. The 5/8-inch Sigma-Flo tube pattern is available with COPPER fins only. The 1-inch Sigma-Flo tube pattern for use with steam coils is available with aluminum or copper fins. Better