The REED R6001 is a handheld dual-display thermo-hygrometer that tracks temperature and %RH simultaneously with a fast 2.5-reading-per-second sampling rate, backed by Max/Min/Avg and data-hold functions. It spans -20 to 60C (-4 to 140F) and 0-100% RH, runs on a single 9V battery, and comes with its own carrying case; optional 33%/75% RH calibration standards are available separately. This listing adds a NIST-traceable calibration certificate to the base unit.