5628 Series - Secondary standard PRT/RTD probes: These probes fill the gap between affordable, but temperature-limited secondary PRTs and more expensive, highly accurate SPRTs. Using a regular PRT at temperatures above 500 °C exposes the platinum to contamination. If the PRT is used as a reference or calibration standard, contamination is a major problem. SPRTs, which are more expensive and delicate, can handle the higher temperatures, but with greater risk to the instrument due to shock, contamination, or mishandling. The 5628 is designed to reduce the contamination risk through the use of internal protection while not impairing performance The 5628 is nominally 25.5W.

Available for sale in the United States and Canada only.

Hart Scientific is now Fluke Calibration.