Hello @ Sori! I got a smartest several months ago and took a chance because of spinal neuropathy. I was hesitant because I have spinal neuropathy and shake rattle and roll really aggravates it! I am sure you know the pain that can ripple thru your body. So I queried the company after approval and they sent me three rectangular foam blocks when put together block the shaking directly on my spine. With that in place, and I limit its use to once a day mainly out of fear that the spinal neuropathy will rear its ugly head. So far so good. I notice that even at once a day (2x a day is recommended) , throughout the day more bits of mucus come up during the day. I hope things work out for you. The company indicated that within a reasonable time after purchase it could be returned. I would think 30 days as they have a billing cycle with Medicare to accommodate patient problems. They really were very nice to work with. Yeah, you gotta do your homework about this stuff. We all are pretty fragile. Good luck and let me know. Sincerely, Nancy Fox