My 13 yr. old occassionally drops his shoulder when batting. A local high school ball player who has been hitting balls with him off season suggested he get a certain type of shoulder brace that doesn't allow you to drop your shoulder when hitting. He said he used one when he was my son's age and it effectively conditioned him to not drop his shoulder. I've looked online, at our local sporting good store as well as the East Bay catalogue and can't find what he is talking about. Does anyone know the name of this product or where I can find it?