Harrows O Rings a dart gasket The Harrows company is the largest manufacturer of darts in the world. Its headquarters is in Hoddesdon in England and right from there all aspects related to design , production and distribution are controlled. Harrows products are designed to completely meet the requirements of all players both beginners as and fully professional. The company is operating on the market already 35 years and its products are available in over 100 countries a over the globe.Rubber anti unscrewing gasketóin from barrel.