These hoops are made from smooth, strong wood. Each hoop is 1" thick/tall for easy gripping and maneuverability. The wood feels good in your hands and grips the fabric without harming it.
A long screw is threaded through two small blocks of wood at the top of the hoop. Use the wingnut to loosen or tighten the hoop. These wood blocks are helpful handholds as you work.
This 14" hoop is the size I use most often.