The style you choose will come in the matching finish you choose. For example, if you choose a rose gold finish, you will receive a rose gold labret to match. All design choices are available for each finish except for one, the 18G Ball with CZ, that is only available for the steel finish. You will note this in the list of style options.

In all Labret styles the mm, such as 6mm, 7mm, 8mm represents the post length, which is the wearable length measured from the bottom of the labret to just underneath the ball that screws on the top of the labret. All styles of the ball itself measures approx 3mm.
Labret Post Length: Available in 6mm, 7mm, or 8mm