Quote Originally Posted by Duff
I believe they are called, "Locking Tone-Pro" bridges. I have one or two on some guitars, my Epi LP Plus top and I think my MK. Regular "Tone-Pros" that I have are not locking.

Although, according to the Gibson tech guy my new Epip LP Tribute has locking tonepros. But there are no allen screws. So I called and he said they have a new design locking tonepro that uses a spring mechanism inside the bridge and tailpiece.

Would the gibon guy lie to me????? They have had participated in some unethical practices lately: like the nondisclosure of weight relieving and chambering until some dudes saw xrays of their "solid body" LPs and were supposedly shocked by what they saw. Only then, years after the production method had been implemented, did gibson disclose the practice. Possibly a trade secret. They now include the chambering description in the chambered guitars, which is almost all gibsons except for custom shop models.
H'mm I dunno... I had another look over the TonePros website and from what I can see, all their models have locking screws. Without the locking screws it's just a probably a regular Gotoh set or a copy of one.

The new Epi tribute doesn't use a TonePro's bridge and tail. It uses a "LockTone" set that, as you say, has some kind of spring retention mechanism.

I have no idea if there's any difference tonally between the TonePros and the LockTone, but they are different products.