Pipe Insulation Insulation Material Buna-N Rubber Installation Style Unslit Inside Diameter 4 in Wall Thickness 3/4 in Overall Length 6 ft Minimum Operating Temperature -297 Degrees F Maximum Operating Temperature 250 Degrees F Facing Material Unfaced Color Green R Value 3.2 Form Tube For Copper Tube Size 4 1/8 in For Pipe Size 3 1/2 in Flame Spread Index 137 Smoke Developed Index 162 Foam Cell Type Closed Plenum Rating Plenum Rated Flexibility Flexible