The Amprobe TH-1 relative humidity (RH) and temperature meter simultaneously measures relative humidity, dew point, and wet- and dry-bulb temperature to provide dual-scale readings in F and C, and is used for HVAC, indoor air quality, and environmental applications. The capacitive humidity sensor measures RH from 0 to 100 percent. The extended probe has a cover to protect the sensor when taking measurements inside ducts. The meter has minimum, maximum, and hold functions for recording data, and relative zero functionality stores reference points. It requires one 9V battery (included), and includes a carrying bag, and instructions.Specifications Temperature range -4 to 122 degrees F (-20 to 50 degrees C) Temperature accuracy + or - 1 degree F (0.6 degree C) RH accuracy + or - 4 percent from 10 to 95 percent RH, and + or - 5 percent at all other readings Wet bulb range 23 to 139.8 degrees F (-5 to 59.9 degrees C) Wet bulb accuracy + or - 1 degree F (0.6 degree C) Dew point range -4 to 139.8 degrees F (-20 to 59.9 degrees C) Dew point accuracy + or - 1 degree F (0.6 degree C) Resolution 0.1 percent, 0.1 degree (F or C) Sensor hysteresis + or - 1 percent RH Operating environment at less than 80 percent relative humidity 32 to 104 degrees F (0 to 40 degrees C) Storage environment (with battery removed) at less than 70 percent relative humidity 14 to 140 degrees F (-10 to 60 degrees C) Dimensions 6.89 x 1.65 x 0.63 inches (175 x 42 x 16 mm) (H x W x D) Weight Approximately 6.4 oz. (180g) Standards met EN 50081-1/1992 : EN 55022, EN 50082-1/1997 : EN 55024, (EN 61000-4-2/-3/-8, ENV 50204) H is height, the vertical distance from lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back. A thermohygrometer is a combination thermometer to measure temperature, and hygrometer to measure humidity. It monitors relative humidity and temperature in lab, office, home, and greenhouse applicationsAmprobe manufactures electrical testing equipment for commercial, industrial, and home use. The company was founded in 1948 and is headquartered in Everett, WAWhat’s in the Box? TH-1 relative humidity meter CR2032 battery Instructions