Cornwall Quality Products, Mogadore Ohio made this a long time ago. I got it at an auction for a service station closing ago ut 40 years ago
Is it complete? I guess you could flip it 180 to check the other side so long as there is a stop of sorts in that design that I’m not seeing.
We did them on the run with the stock cars, if the steering wheel was off, no biggie. I marked "center" on the wheel with tape anyway. It is however nice to see some old and conjured up tools that are at least fairly accurate.
Masonite plates with grease in between them, and some toe plates from the stock car days. Confirm steering wheel center with a string line to the rear wheels. Make certain your runout is not excessive, and be sure you have matching tape measures for the toe plates, some have a little more slop than others.
One thing that no one has mentioned. If you are measuring off the tire sidewalls, you should first jack it up, spin the tire, and find the “high point” of the sidewall. Put a mark on that spot. When you are measuring the toe put that spot either straight down or straight up. That will give you a more accurate measurement.