The high-temperature head fits directly onto the shaft of a standard ReactionView&trade probe, and provides cooling using a flow of either room-temperature or cooled gas (air or nitrogen). An optical coupling crystal inside the head carries the mid-IR signal to the end of the probe, which can be fitted with an ATR crystal or a transmission head. A choice of standard reactor fittings can be included on the head (0.5" X 20 Dynisco or 9/16" HIP). The Remspec high-temperature had has been tested up to a reactor temperature of 250 C, and has been used at pressures over 200 bar.