An array of bits you can find on the market, renging from four point pressure bits, three ring snaffles, corkscrew bars with curb chains and gag bits that work on poll pressure
I must say I’ve seen some strange bit choices especially in the endurance scene, for some reason it seems to be all the rage to have these outrageously severe bits. People actually have the audacity to ask for the strongest bit available in that store, we are talking, chains, shanks, gags, nose pulls (both metal and rope) as well as mechanical hackamores, believe it or not but you can even get a combination of most of these, in a "one stop shop" bit.
The question that pops into my mind is, Is this purely an attention seeking exercise? Is the hunk of metal going to make you appear as a serious rider? And why is it seen on completely novice riders who are competing in their first race? If you don’t understand the mechanics and severity of the machinery your attaching to your horse’s mouth then I would suggest you do your research and talk to several very advanced riders, get some advice before you go down this path. Strong and severe bits should only be used by advanced riders who are capable of riding a horse without dispersing excessive load onto a horse’s mouth, actually you should have very subtle and soft hands! (generally you see novice riders using the reigns as a form of balancing themselves or they simply seesaw or perform other hideous movements from unskilled and heavy hands).