Certified hygrometer is certified to be accurate within +/- 3% RH. The dial indicates the complete range of 0 to 100% relative humidity. Each instrument has been tested at three different positions of the dial at temperatures ranging from 32 to 230 degrees F.

Calibration certification is provided. The Bimetallic thermometer on the HTAB-176 is accurate to 1% of scale with a range of -20 to 100 degrees C and 0 to 210 degrees F.

- Color differentiated scale which reads in Fahrenheit and Celsius
- Brass case