That picture brings back memories! We sold a fair number of squash bats in the '70s...most for use at USC(the original...South Carolina), a very few for Ft. Jackson Army Base. Thankfully, the vast majority were prestrung; but we did carry some tournament sticks that were sold frame only and a few customers wanted Victor Imperial Blue Spiral nat gut

. We'd get the odd Grays racket in from time to time or even a Slazenger or two when the 'northerners' would come to town.If you take a look, that's a lot of strings in a very small space. Installing 15ga nat gut or Ashaway Vantage was NOT the highlight of any day!
Good news was most of the pre-strung bats broke from impact before needing restringing.
And don't forget the terry cloth grips for those!!!
Ah, the good old days!