Calibration salts for all Rotronic Probes and Handhelds. These salts are designed to be used in conjunction with the Rotronic calibration chambers. You will then be able to calibrate your probes or handhelds to 50%rh and if necessary make any adjustments. There are five vials in a pack allowing you to calibrate your probe or handheld annually for the next five years. Doing calibrations in house will save you money as you no longer need to send your instruments away to a third party. 0.5%, 5%, 10%, 11%, 20%,35%, 50%, 60%, 65%, 75%,80% & 95% humidity standards are also available. Please contact us for details.