Insulation Sheet, Insulation Material Buna-N Rubber/PVC, Insulation Color Black, Overall Length 4 ft, Overall Width 36 in, Thickness 1 in, Minimum Operating Temperature -40 Degrees F, Backing Type Plain, Maximum Operating Temperature 220 Degrees F, Jacket Material Unfaced, R Value 4, Form Sheet, Flame Spread Index 25, Smoke Developed Index 50, Foam Cell Type Closed, Plenum Rating Plenum Rated, Flexibility Flexible