These 3" foam blocks are made from a sturdy, scratch resistant foam. Each block has beveled edges for added comfort. You will find these blocks to be very strong and durable, and yet incredibly lightweight and comfortable. Foam blocks lend support and extension to yoga postures. They provide the support and/or height needed to do poses safely and effectively. When placed under the hips, hands, heels, or between the hands, they provide the stability and grounding needed to extend fully.