Pipe Fitting Insulation Insulation Material Buna-N Rubber/PVC Installation Style Unslit Inside Diameter 2 7/8 in Wall Thickness 1 in Form 90 Degrees Elbow Minimum Operating Temperature -297 Degrees F Maximum Operating Temperature 220 Degrees F R Value 6.4 Color Black For Pipe Size 2 1/2 in Flame Spread Index 25 Foam Cell Type Closed Plenum Rating Plenum Rated Flexibility Flexible For Tube Outside Diameter 2 7/8 in Resistance Properties Antimicrobial Flame/Fire Retardant