I was in high school in 1973 we had one like this I don't remember the model. Then I found a Sun 404, the right after that I found a Allen. I liked the Allen better a sold the 404. Then came across a Sun DT-1, it works but some of the gauges do not. The manometer has rusted up, down and all around? This came along so it will look good with Sun 620 Gen/starter tester. It takes me awhile standing in front of them for it all to come back to me. But it's fun running and restoring old parts I just don't do a lot. otice I didn't mention engine analyzers, they are in the garage I have a few, the go to machine is a 1980's 1115 that I got in a post service auction. I do like well made in the USA tools and machines!