Pipe Insulation Insulation Material Melamine Installation Style Hinged Inside Diameter 4 1/8 in Wall Thickness 1 in Overall Length 4 ft Minimum Operating Temperature -40 Degrees F Maximum Operating Temperature 350 Degrees F Facing Material Unfaced Color Gray R Value 4.66 Form Tube For Copper Tube Size Not Applicable For Pipe Size 3 1/2 in Flame Spread Index 25 Smoke Developed Index 50 Foam Cell Type Open Plenum Rating Plenum Rated Flexibility Flexible