The test fixture belongs to a category below the fixture, which is a fixture that specifically tests and tests the function, power calibration, life, performance, etc. of the product. Because it is mainly used for testing various indicators of products on the production line, it is called a test fixture.

Many fixtures are produced because of commercial needs, because there are many types of fixtures that are customized, some of which are to increase productivity, repeat specific actions, or make work more precise. Because the design of the jig is basically based on logic, similar jigs may be generated separately for different times and places. The advantage of using a jig is that if it is the same product, even if the worker does not have very skilled technology, it can quickly produce a large number of good products with fewer defects and low variability by the jig. For a variety of small production modes, the result of many fixtures, on the contrary, causes the disadvantage of increased production costs.

Fixtures focus on work and guide tools; fixtures focus on holding tools in a fixed position. Some devices that have both functions (control and guide tools) are also referred to as jigs, but devices that only hold but not guide tools are referred to as "fixtures" rather than "fixtures." After entering the era of CNC systems, the use of jigs has been reduced.

After entering the automation and CNC system machines, the jig is no longer needed because the tool path has been digitized and stored in memory, but the "fixture" is still generally used.