The professional polyurethane surround has a thickness of approx. 3.5 cm. The polyurethane material protects the wall from damage and minimizes the number of darts falling down, which also protects the darts and the floor. The new, improved fit with an inner diameter of approx. 45 cm fits perfectly on every bristle dartboard we know of. -> One size fits all. The catch ring can be easily mounted on the dartboard. The width of the protective ring is approx. 12 cm, which offers enough protection for the wall, even for inexperienced dart players.