I wouldn't go by that label on the magnet. Measure the diameter of the cone and the size of the frame. Most coned drivers have those measurements listed in their specifications.
Here is a
Poly planar marine speaker that mounts in a 2.6" hole and has an included locking ring (no screws necessary). I have no history with this driver.
Here is a
Peerless full-ranger that is 2.5". I've used some Peerless drivers with good success.
You will probably find more offerings in 2.5" than the Asian 66MM size. I don;t think that 0.1" is going to make a difference. As said go by cone diameter and frame size for best fitment.