The 3125 is a true calibration instrument with a uniform surface temperature that reaches temperatures as high as 400°C. The test surface is milled aluminum for an absolutely smooth and true calibration work area with maximum thermal conductivity. The 12.25-square-inch test surface is large enough to calibrate more than one sensor at a time. The 3125 can be used with a reference surface sensor or PRT. PRTs (3/16" diameter, such as the 5615) may be inserted through a drilled hole into the center of the block for use as reference thermometers or for easy recalibration of the unit’s display.

With an accuracy of +/- 0.5°C to 200°C and +/- 1°C to 400°C, you can calibrate almost any surface probe, thermistor, thin film sensor, RTD, thermocouple, ribbon sensor, or surface mount cutouts, fuses, and switches. Stability is within +/- 0.3°C at 400°C and uniformity within the center three inches of the surface is +/- 0.6°C at 200°C.