Ok, I'm a little confused now. So the below release is a "true BT" release and it has a thumb post. Thumb trigger releases also exist but they are not considered "true BT", correct? Then a rotary type release is made as well according to this site
http://www.koniaris.com/archery/mrd/ which is not considered BT. The black release below is a thumb trigger release that a friend let me borrow. I tried it for the first time today.[:-] The bowstring only releases once the thumb trigger is pressed and then let up until a click is heard. Man, I anticipated the shot badly. As soon as I pushed the trigger I was ready to let my bow down. I knew how the release operated but its just a bad habit I have. I really need to get these issues solved.
http://www.truball.com/TRUTension.html
Thumb trigger release