see appendix IV of the rule book, 4 items listed about tees. I’ve been working tournaments for 10 years and I have never heard the question come up about tees. But if in your mind you are using it as an aiming device, I would rule against you BUT what are the chances of it coming up. It all depends on what your intent was for the tee. JMO. While looking at that, also look at “GLOVE”– is the glove with raised ribs to help with swollen fingers legal (how many people will have something to measure 0.635 mm with them to measure). I looked at several of the tees being sold last year and never saw a sign that said it was approved by USGA or not. IF the “intent” is to gain an advantage, it is probably against the rules, but I seriously doubt it will come up.