I was surprised at how well made the blocks are. The material used looks like leather and it covers real wood blocks, not some type of fiber fill. They are very sturdy, don't slide around and stay where you want them. I also like that they have handles to make it easier to pick up.
My chiropractor recommended I use the blocks to help with my pelvic imbalance. I use to have terrible leg length discreptancy before, but since using the block, I'm 90% more even, consistently, which has aleviated some of my sacral and S-I pain. I would highly recommend.