18" Insulated Aluminum Flexible HVAC Duct R-6.0 – 25' Length return filter R value rating of insulation

R value rating of insulation - r3

The smooth

Actual Filter Size – 35 3/4"w x 31 3/4" x 1"

Actual Filter Size – 19 3/4"w x 15 3/4" x 1"

protecting it from outside elements

18" Insulated Aluminum Flexible HVAC Duct R-6.0 – 25' Length return filter R value rating of insulation+ Product Details High Quality Aluminum housing on the outside and on the inside for the best insulation value Insulation A thick blanket of fiberglass insulation provides you with an R Value of 6. 0 Energy Efficient Air tight inner core decreases the pressure loss and provides a more hygienic environment high energy efficient No fiberglass erosion into air stream Design Designed to withstand bends and sharp turns without kinking. Tough reinforced