The ISOFLOW cooled mirror technology was developed at Itek with the goal of producing a high performance heat exchanger with emphasis on coolant efficiency and low jitter. Design and analysis capabilities, as well as manufacturing processes were developed and demonstrated in 8.0 inch diameter mirrors made from single crystal silicon, silicon carbide, and Ultra Low Expansion glass. The ISOFLOW mirror design has been tested and has demonstrated excellent thermal distortion for very low coolant flowrates and pressure drops. The ISOFLOW mirrors have been polished to better than 3 angstroms rms. The mirrors are bonded with a composite lead borosilicate glass frit blended to match the heat exchanger materials. The heat exchanger was designed to operate over a wide flow range with water or ammonia as the coolant. The high performance turbulent flow regime requires 20 gpm with a 40 psi pressure drop through the mirror. The mirror can also provide low flow low jitter operation with 6.6 gpm and 4.5 psi pressure drop. The demonstrated thermal performance obtained with low flowrates and pressure drops is what makes the ISOFLOW design unique.