Nurge embroidery hoops are of superior quality and are made from hard beech wood. These are finely sanded and hand polished for a super-smooth natural wood finish. The adjustment screw and threaded angle bracket fittings are made from pure brass and polished for a rich, striking gold color look. This improves the presentation of your work. The diameters of the beech hoops are from 100mm (4″) to 310mm (12″). The diameter is taken from the space between the inner & outer hoops. These are 8mm (0.31") deep.