Instrumentation amplifiers are not a specific brand but a category of precision amplifiers used in industrial and scientific applications. They are produced by various companies worldwide, including Texas Instruments (USA), Analog Devices (USA), and STMicroelectronics (Switzerland). These amplifiers are designed for high accuracy, low noise, and excellent common-mode rejection, making them ideal for medical equipment, process control, and data acquisition systems. Key products include integrated circuits (ICs) like the INA128 (Texas Instruments) and AD8221 (Analog Devices), which are widely used in signal conditioning and measurement systems.