I like knobs
Crutchfield Customer Review (What's this?)
This is a fun little gizmo to install in your dashboard. Do you need it? Probably not. Is it easy to install and nice to have? Certainly. I also find it useful to control bass level between songs to reduce rattles on my rear deck (which I am going to sound-treat, but have not yet gotten around to).
Pros: - Easy wiring - Easy to flush or surface mount - Easier to use than head unit sub control
Cons: - Difficult to separate from mounting bracket (instructions are a bit incomplete, and it is glued on as well as screwed). - Large footprint near mounting surface required a bit more Dremel-ing of the dash than I would have liked.