This stainless steel high-temperature air-to-air heat exchanger uses a fully welded stainless steel plate pack with no elastomer gaskets, eliminating aging concerns. It operates continuously in 350-600°C flue gas or corrosive gas streams. Two gas streams flow counter-current on either side of corrugated plates, transferring sensible heat through the stainless steel walls with high efficiency, low pressure drop and long maintenance-free intervals. Widely used in industrial furnace flue gas heat recovery, high-temperature process gas exchange and drying exhaust energy recovery.