difference between surcingile and roller

Question
hello madam, what is the difference between surcingile and roller??

Answer
a sircingle straps around the horses rib cage then it has side reins to teach the horse to break at the poll and give in to pressure. you can also use it to ground drive a horse. i have never heard of a roller, sorry i cannot tell you the difference. perhaps if you show me a picture of one i can help more