Difference amplifiers are not a specific brand but a category of electronic devices used in various industrial applications. These amplifiers are designed to measure the difference between two input signals and are commonly used in precision instrumentation, medical equipment, and industrial control systems. They are produced by several manufacturers worldwide, including companies like Analog Devices (USA), Texas Instruments (USA), and STMicroelectronics (Switzerland). These devices are essential in industries requiring high accuracy and noise rejection, such as automotive, aerospace, and telecommunications.