Originally Posted by NLBwell
Didn't Hart have a racket where you could turn a screw and change the string tension (by changing the throat)?
Yes, but it wasn't badged "Hart." Instead it had the manufacturers name "Acro" on it. It was called "Acro - The Adjustable." Here's a picture:
If you look at the top of the grip on all the Hart/Seamless/Seamco rackets you will see the word "Acro." They manufactured all of those rackets as well.