Lowbrets by Brazda. (Patreon)

From the BME Wiki entry:
The vertical lowbret piercing starts inside the mouth between the lower lip and the teeth (not behind the teeth as with a mandible piercing) and travels straight down, exiting on the lower edge of the jawline. This piercing is usually done with a straight or very slightly bent barbell 1.5" to 2" in length depending on anatomy.

Shannon Larratt sent these prints to me in the mid 1990s- he had worked at Tom Brazda's Stainless Studios before starting (and possible in the earliest years of) BME and Tom was his go-to for, "lets see how this works out" piercings like the vertical lowbret, the knuckle piercings, and at least two uvula piercing attempts.