Designed to eliminate line twist and make a dependable and strong link between the main line and a leader. The Mustad Rolling Swivel with Diamond Eye is made from high quality materials and will not let you down. The diamond shaped eye at both ends of the swivel, guides the line to stay centered, keeping knot in-line for maximum rotation. The rolling swivel design makes them perform better when under load, with the swivels still able to spin and reduce line twist when placed under considerable pressure. When choosing a swivel always go small. Pick a swivel that matches the breaking strength of your line. This will give the best performance and presentation. Made from brass, for either salt or freshwater use. Black nickel finish.