LOL... I feel like I won a prize!!!!
That bit was actually kind of hard to find on line.
What I learned today is that the calvary style shanks are swept back making it less harsh and that the Billy Allen mouth piece is also forgiving as opposed to a Tom Thumb that will jut forward (nut cracker action) when you pull back on the reins. Like backing up for example. On top of all that I also learned that the way that this bit. (Bill's) connects the mouth piece to the shanks is very gentle for the horse (no pinching).
Bill, Thank You sincerely for taking the time to get some pictures and post what you use for us. I value your years of experience and am glad you stick with us on these topics!