I'm pretty familiar with most types of bits and bitting arrangements, but I've never seen something quite like this. Is anyone familiar with this bit or have any idea what it's called and how it functions?
Ah, nevermind. I finally found something. I had to adjust my search terms a bit.
It's called a Wilson bit. Primarily used as a driving bit but occasionally used for riding horses. It works with a squeezing motion on the sides of the horse's face, rather than at the corners of the mouth. (Credit)
I believe it is a type of snaffle bit; don't know what the mouthpiece is like though as that can come in different styles. I've seen them used before on jumpers and assume that is because the design keeps the bit alittle more stable in the mouth.