I first saw the Flex-Head Golf Tees on My Golf Spy's website, and was intrigued enough to order a set. Although selecting the correct tee for my each of my clubs took a bit of trial and error (well, lots of error), once I got things figured out, I became a "Flex-Head" myself. (Apologies to Jimmy Buffet and The Grateful Dead.)
These tees work as advertised. They have proven to indeed be unbreakable, even after being subjected to some pretty horrendous mis-hits. The bright colors ensure I can track 'em down on the tee-box, so I haven't lost a tee either. More importantly, having a consistent tee/ball height for my driver, fairway wood, hybrids and irons has likewise improved my consistency tremendously! I get a clean ball strike as a reward whenever my swing goes the way it's supposed to, and that formerly rare event occurs much more frequently thanks to my increased confidence at address.
I'm not sure if my enthusiastic sales pitch to my golf buddies has resulted in any orders, but I did purchase a double set as a birthday present for my younger brother (who is a much better golfer); since he's a professional salesman, be prepared for an onslaught of orders from Texas real soon!
Cheers, Dave Hall, Steilacoom, WA