Pipe Insulation Insulation Material Cellular Glass Installation Style Slit in Half Inside Diameter 1 3/8 in Wall Thickness 1 in Overall Length 2 ft Minimum Operating Temperature -450 Degrees F Maximum Operating Temperature 900 Degrees F Facing Material Unfaced Color Black R Value 3.45 Form Tube For Copper Tube Size 1 3/8 in For Pipe Size 1 in Flame Spread Index 25 Foam Cell Type Closed Plenum Rating Plenum Rated Flexibility Rigid For Tube Outside Diameter 1 3/8 in