It can be seen here at joanns
Was wondering if anyone had one and if it worked… 
I knit using the English style so I’m not sure that would work for me. I carry the yarn between my thumb and forefinger, across my right palm, and between ring and pinkie fingers. That seems to control my tension just right.
However, I do use Thimble-its sometimes when needle points cause discomfort. They work very well.
I have used something similar when doing double knitting http://www.joann.com/catalog.jhtml?CATID=82328&PRODID=11836&source=search] the clover yarn guide
I knit lever style (English but with a lever motion instead of a full throw) and my daughter knits continental and she uses one when she double knits also.
I don’t use it otherwise, and while it does the job, it’s rather cheaply made and I’m not sure how well it will hold up over time. So far it’s gotten me through a few pairs of socks that I double knit the foot on though!
Mama Bear