Compact and portable, the BBS500-57 blackbody radiation source is ideal for use in the verification and calibration of non-contact infrared thermometers, infrared detectors and thermal imaging camera systems. With a temperature range of 122-932°F (50-500°C) and a large aperture opening of 2.25 inches, it allows for calibration of optical variations in a wide range of infrared thermometers. Higher precision measurements are achieved using a contact calibration method via an RTD inserted into a well that is located directly behind the target surface. With use of an optional digital RTD thermometer and calibrated secondary probe, accuracies of ±0.1°C can be realized.