The Extech HD200 differential thermometer data logger and IR thermometer is perfect for taking differential temperature readings with dual Type K thermocouple probes plus non-contact surface temperature measurement using an IR thermometer probe. The Extech HD200 differential thermometer data logger and IR thermometer logs up to 18,000 readings on each channel. The following readings can be displayed [T1, T2, T3(IR)] or [T1 - T2] or [T2 - T3]. The differential T1 - T2 display is excellent for HVAC / Superheat measurements. The Extech HD200 differential thermometer data logger and IR thermometer features heavy duty rugged double molded housing, MAX/MIN/AVG and Data Hold functions and user selectable 1° / 0.1° resolution. The included IR thermometer probe can be used to measure non-contact surface temperatures up to 1022°F (550°C).