Pipe Fitting Insulation Insulation Material Buna-N Rubber/PVC Installation Style Unslit Inside Diameter 3 1/8 in Wall Thickness 1/2 in Form 90 Degrees Elbow Minimum Operating Temperature -297 Degrees F Maximum Operating Temperature 220 Degrees F R Value 4.6 Color Black For Pipe Size Not Applicable Flame Spread Index 25 Foam Cell Type Closed Plenum Rating Plenum Rated Flexibility Flexible For Tube Outside Diameter 3 1/8 in Resistance Properties Antimicrobial Flame/Fire Retardant