Cord vs string vs elastic.
Why we use 1.5mm braided polyester and not paracord, fishing line, or bungee.
Braided polyester at 1.5mm
The right answer for nine out of ten golf-tether use cases. Holds a bowline without slipping. Does not stretch under load. UV resistant. Cheap. Cuts cleanly with scissors.
Why not paracord (550)
Too thick. Adds visible bulk in the swing line. The inner cores can shift inside the outer sheath, fraying the knot over time. Paracord is for backpacks, not golf tees.
Why not fishing line
Monofilament cuts itself when bent sharply at the knot. Braided fishing line works mechanically but is hard to see, and an invisible cord across a hitting mat is a tripping hazard.
Why not elastic or bungee
Elastic returns the tee with momentum. That sounds good and is actually bad: the tee comes back with enough energy to bounce out of position, or worse, sling toward your face. Fixed-length cord lets the tee return at gravity speed, which is what you want.