The Reflectix® Duct Insulation Spacers are for use in conjunction with the Reflectix® Duct Insulation. The spacers are easy to work with and provide an enclosed air space between the duct and the insulation. The enclosed air space (and number of enclosed air spaces) determine the R-value for that particular system. The Reflectix® Duct Insulation spacers are available through HVAC Products Suppliers. Reflectix Corner Spacer, 2 in Length, 2 in Width, 3/4 in Thickness, 250 deg F, Plastic, Domestic