KeyBar MagNut Aluminum 1in Overall 0.5in Diameter Split Ring. Set includes two MagNuts (left and right) each with 0.5" diameter split ring. 0.25" x 0.25" rare earth Neodymium Iron Boron magnetic cylinder insert which has a pull force of 6.5 lb. Manufacturer's Warning: Caution: Do not wear with pacemaker. Clam packed. Package Contents: KeyBar MagNut Aluminum KeyBar MN-AL: MagNut Aluminum 1in Overall 0.5in Diameter Split Ring