double bubble foil insulation r value

Foil Backed Heat Insulation Film, Thermal Raidant Barrier Sheet, Pipe Wrap, Building Roof Thermal Insulation Key Parameters: Size: 6 inch x 25 feet; Material: aluminum foil; Instructions: Wrap it around pipes or ductwork, overlapping about every 1/2-inch as you use 10mm-Diameter Double Bubbles: 10mm-diameter single bubble; double bubble insulation's benefits are to provide airspace between the pipe and wrap that will aid the insulation value

Foil Backed Heat Insulation Film, Thermal Raidant Barrier Sheet, Pipe Wrap, Building Roof Thermal Insulation Key Parameters: Size: 6 inch x 25 feet; Material: aluminum foil; Instructions: Wrap it around pipes or ductwork, overlapping about every 1/2-inch as you use 10mm-Diameter Double Bubbles: 10mm-diameter single bubble; double bubble insulation's benefits are to provide airspace between the pipe and wrap that will aid the insulation value

...Bubble Foil , Aluminium Silver Bubble Sheet Alu-bubble foil specifications : Item Name Aluminum Foil Bubble Insulation Material Structure Alu/Metalic+Bubble Alu/Metalic+(single/double)Bubble+Alu/Metalic Alu/Metalic+Woven+Alu/Metalic Alu/Metalic+Woven+Alu/Metalic Roll Size W. 1.2m x L. 30m/40m Bubble Size Φ10~20mm,H3~5mm Product Thicness 3~8mm GSM 180~410 g/m² Density 431g/m² PROPERTY STANDARD UNIT VALUE