The unit is considered a Controlled Hunt because you have to apply for it in the draw (cant buy a tag OTC). Its an unlimited unit, but you have to apply for it as your first choice. If you wanted to apply for a hard to draw unit and then 73 as your 2nd choice, you would not draw. Works similarly to the same way it is in Montana's unlimited Deer permits, but in MT you can get a unlimited permit as your second or third choice, not this unit in ID.
There is also another controlled hunt on the unit that allocates 5 tags for later season dates, and is really hard to draw.