Self-Seal Insulation Insulation Material EPDM Installation Style Slit with Adhesive and Flap Inside Diameter 2 1/2 in Wall Thickness 3/4 in Overall Length 6 ft Minimum Operating Temperature -297 Degrees F Maximum Operating Temperature 257 Degrees F Facing Material Unfaced Color Black R Value 4.5 Form Tube For Copper Tube Size 2 1/2 in Flame Spread Index 25 Smoke Developed Index 50 Foam Cell Type Closed Plenum Rating Plenum Rated Flexibility Flexible