Only MTCW is perverse enough to design a part this brilliant.
What's perverse about it? - $176 price tag for a drag knob - and worth every bit.
MTCW calls it TD System for Touch-Drag.
The stock plastic lump drag knob contains threads, detentes, and a clicker.
Note how the MTCW part is thicker. It's also lighter than the stock drag knob.
It's all metal, has twice as many detentes per knob rotation, and there's a spring inside.
They give you a choice of springs - the red spring is stiff and gives you the full drag the spool is capable of.
The silver spring is softer, only gives you up to about 2 lbs drag, but within that, an amazingly wide range on the drag adjustment.
The soft spring also lets you push the front of the drag knob to add drag, for hook-setting, or slowing a run.
If you think about it, the range on drag set in the stock plastic lump knob results from elastic strain in the plastic as you tighten and compress the knob.
The elastic range in the spring is 100 times greater.
Tom and I were talking about this offline and he asked about the difference between 4 and 8 ounces of drag.
I'd guess it's probably two full rotations of the knob to set that difference.
I've been fishing one of these on my Vanquish since the second time I used it.
Recently added one to my C1000S for my second XUL rod.
My C2000SHG on Black Hole UL rockfish doesn't need it, because that rod is capable of 10-lb line.