HardDon gave me a harddon time bout the description.
This material seems to work very nice for my Arena

Reflectix® is a 5/16" thick, seven layer, reflective insulation
Two outer layers of aluminum foil reflect 97% of radiant heat. Each layer of foil is bonded to a tough layer of polyethylene for strength
Two inner layers of insulating bubble pack resist conductive heat flow while a center layer of polyethylene gives Reflectix® high reliability and strength
Reflectix® reflects the sun's rays in the hot summer months. It also retains interior heat and helps to eliminate potentially damaging ice dams during the winter months