Pipe Fitting Insulation Insulation Material Buna-N Rubber/PVC Installation Style Unslit Inside Diameter 4 1/2 in Wall Thickness 1/2 in Form 90 Degrees Elbow Minimum Operating Temperature -297 Degrees F Maximum Operating Temperature 220 Degrees F R Value 3.2 Color Black For Pipe Size 4 in Flame Spread Index 25 Foam Cell Type Closed Plenum Rating Plenum Rated Flexibility Flexible For Tube Outside Diameter 4 1/2 in Resistance Properties Antimicrobial Flame/Fire Retardant