What is the purpose of this bit?

It is an 'Elevator Gag' also commonly called a Wonder Bit. It is a curb, and a gag bit and obviously needs someone with soft hands who know what they're doing.

I own several with simple jointed mouth pieces, and I really like them because I know what I'm doing. With very light touches when it's on a horse properly, it only puts a little bit of pressure. I actually used one to retrain a gelding who had been abused extensively in the mouth, and he loved it. He responded very well, because when used right, it can be very forgiving.

See, the mouth piece slides. The more pressure, the higher it slides up.

I usually ride my horses with just a snaffle, and don't usually see any reason to go beyond a snaffle, but elevator gags are not awful like some people seem to think. (Of course, when the reins are in the right hands.)

You want nasty... http://www.bedfordtack.com/catalog/images/5-ring%2...

That one is just crazy. Not only is it double twisted, and has long shanks. It has extra leverage, because of the length of the Purchase.

Add:

I thought I kind of explained a little, but I'll do do again.

In proper hands, you can use it to achieve very light pressure in the mouth. Or more if you so deem fit. It also, with light touches can give the horse a bit of a warning, instead of immediate pressure like a lot of curb bits.

In beginner, or just plain hard hands, it can be damaging, because it's a curb bit and curb bits can put an extreme amount of pressure on the horse's mouth. It also, because of the curb chain, tear up the skin underneath their chin.

Because Curb Bits put that much pressure, you can do serious long lasting damage to a horse's mouth. Such as nerve damage. I had a gelding once who seemed to have no feeling in his mouth at all, and he had to be taught to neck rein, and other things, like stopping due to the rider's shift of their weight.

You can also damage the bone.

I would never put a gag in a horse's mouth for beginners to ride. Perhaps a really advanced beginner if they showed that they had really soft hands, but a lot of beginners yank on mouths too much.

Well...a lot of riders do far too much yanking on mouths. They don't have much concept on how they work, and the pressure that they're applying. even if they teach you about Leverage in school.

Ok. Firstly you need to check that your horse has not got a small mouth or a big - rubber bits can be wide and not very comfortable on some horses. Personally, I use a french link (it might be called something else in the U.S). Its basically a snaffle bit with 2 joint. It has less of a nutcracker motion in the mouth and so is milder than a normal single jointed snaffle. But DO NOT confuse it with a Dr Bristol which looks similar but the central bar is designed to dig into the tongue - avoid that as it is a very strong bit. Some people like to use bits with cheekpieces as the cheekpieces help to guide the horse in the right direction without pulling on the mouth too much, and also help to prevent a bit sliding straight through the mouth (although I can't see how anyone can mange to do this!!). At the end of the day its a personal choice. Edit @Bliss - lol. No worries. Its just proof that great minds think alike!!!

I second what Ehawlz said.

I have one too, it's called a Wonder Bit, ot elevator gag.

It can be harsh if you won't know how to use it, but if you use it the way it is meant, it's a very good bit. It allows the horse to learn to respond to soft pressure before th bit is fully engaged.

I recently switched my horse from the wonder bit to an eggbutt snaffle. The wonder bit obviously didn't ruin his mouth because he acts just the same with it or with the snaffle. Except he is being stubborn about keeping his front end up, because the wonder bit/elevator gag encourages "lift," hence the word elevator.

Yes, this bit would be harsh int he hands of a beginner. Especially if you have fast and rough hands. This bit is meant to teach the horse to give to small pressure, so if you're always using full pressure, the bit is not being used as it should be.

the round part of this bit is like a snaffle but the rings below are for better and faster stops it is also is for more control