The CL-355A portable dry block calibrator is compact, lightweight, and offers fast heat-up and cooldown times with excellent performance specifications over a large operating temperature range. Whether on a lab bench or in the field its portability makes it an excellent choice. The calibrator will operate over the temperature range from 5 °C above ambient up to 400 °C using a multi-well machined aluminum insert block to transfer heat to the sensors under test. The CL-355A uses the same aluminum inserts as the CL-740A calibrator. This calibrator is designed to work safely under the following conditions: ambient temperature range: 5 to 40 °C, up to 95% relative humidity, non-condensing.