This is one of the very first engine testers. Unlike today, garages did not have anysort of computer or mechanical systems to test engines or other aspects of cars. This engine tester was one of the very first developed, and would have been a huge help to the garage owner. No longer did he have to go over every part of the engine manually, he would just need to attach this engine tester and it would narrow the problem down in minutes, instead of hours.

To have an engine tester like this meant that the garage owner was very prosperous, and was very good at his business. After he purchased the tester, it would have made him even more prosperous. He would be able to fix cars much faster than any competing garage without a tester. It was truly one of the first steps towards a fully automated service like most garages have today.