Bubble insulation aluminum/polyethylene"double bubble" 5/16 inches thickness size ins. X 48 feet x 50 bubble insulation aluminum/polyethylene"double bubble" size 4 feet x 50 Safe to use; non-toxic; easy to install. Does not require special protective clothing. Lowers air conditioning/heating costs. 5/16 inches thick, multi layer, double bubble reflective insulation in rolls of various widths and lengths. Reflects 94% of radiant heat. Class 1, Class A fire rating. Seams should be sealed with TVM Metalized Tape for maximum effectiveness.