Make SURE these are turned so they are laying flat, like a watch band. You might have to make a few twist to get it flattened, but once attached it should always be correct.
proper adjustment of the curb chain is very important. If the curb is too tight, there will be constant uncomfortable pressure on your pony's chin groove and bars of his mouth. This also makes the rein aids exaggerated, which could cause them to toss their head or open their mouth.
Leaving the curb too loose or off is not your solution. An old timer's rule of thumb is 2 fingers between the chin groove and the curb strap/chain.
when using a bit with no shanks, the strap will help to keep the bit from being pulled thru the mouth.
Available in Dark oil, Light oil or Black Works well for your pony or mini