Hanna Digital Refractometers with Stainless Steel Sample Well and 1.5 Second Response Time Hanna digital refractometers eliminate the uncertainty associated with mechanical refractometers. After a simple user calibration with distilled or deionized water samples are measured within seconds. The measurement and temperature, selectable in °C or °F, are displayed on the easy-to-read LCD. With IP65 water protection, these refractometers are durable and compact enough to be used at home, in the lab, or out in the field.