Insul-Rite 5255 and 5155 are the result of state-of-the-art technology and a patented, proven manufacturing process. Polyurethane is continuous foamed-in-place between the inner and outer steel skins to form a homogenous sandwich of steel/polyurethane/steel. This manufacturing technique produces outstanding thermal, strength and bonding characteristics. Close inspection shows that every part of the finished composite is completely filled with polyurethane. The thermal breaks, combined with the high R-value, allow the inside skin of the door to remain at the interior temperature, preventing condensation and frost on the panel.