Counting is one of the simplest basic operations. In digital logic and computing, the counter is the logic circuit that realizes this kind of operation. In the digital system, the counter mainly counts the number of pulses to realize the functions of measurement, counting, and control. It also has the function of frequency division.

This is a portable handheld air quality particle counting meter or particle counter used to monitor particulate matter (PM) concentrations in the air. Designed to aid in indoor air quality (IAQ) assessments, this particle counter also measures air temperature, dew point and relative humidity.

They are sometimes called laser thermometers as a laser is used to help aim the thermometer, or non-contact thermometers or temperature guns, to describe the device's ability to measure temperature from a distance.

The thermo-hygrometer has an internal sensor for air temperature and humidity. PCE-444 is a combination digital hygrometer and digital thermometer used to measure air temperature, relative humidity, dew point temperature and wet bulb temperature.

Borescopes are used for visual inspection work where the target area is inaccessible by other means, or where accessibility may require destructive, time consuming and/or expensive dismounting activities. Similar devices for use inside the human body are referred to as endoscopes.

The EMF300 is a compact microwave leakage detector for measuring high frequency radiation levels. It's easy-to-use, compact microwave leakage detector designed to measure high frequency radiation levels emitted from household and commercial microwave ovens.

A thermocouple is a sensor that measures temperature. It consists of two different types of metals, joined together at one end. When the junction of the two metals is heated or cooled, a voltage is created that can be correlated back to the temperature.