Pipe Insulation Insulation Material Buna-N Rubber/PVC Installation Style Unslit Inside Diameter 3 5/8 in Wall Thickness 1 in Overall Length 6 ft Minimum Operating Temperature -297 Degrees F Maximum Operating Temperature 220 Degrees F Facing Material Unfaced Color Black R Value 5.5 Form Tube For Copper Tube Size 3 5/8 in For Pipe Size Not Applicable Flame Spread Index 60 Smoke Developed Index 85 Foam Cell Type Closed Plenum Rating Plenum Rated Flexibility Flexible