I have a set of these and they do work very well. They are about 1/4" thick and the foam (blue part) is very firm and dense. I use them to grip the fabric to move it and to spread it out smoothly to avoid puckers. I find they save my hands from getting quite or tired and do a good job of helping me move the fabric if it is the least bit slippery. When I bought them (probably about 6 years ago?) they were called Quilt Sew Easy Discs and were from Heavenly Notions out of Portland Oregon and I paid $19.98 Canadian.