Extech Instruments RH390-NIST Precision Dual Display Hygro Thermometer Psychrometer with NIST
Amazon Price: $325.00 (as of April 6, 2019 10:04 am –
Precision Psychomotor that features the highest 2% RH accuracy with fast 30 seconds response time. This product is NIST Certified which indicates that the product is traceable to standards provided by the National Institute of Standards and Technology (NIST).