18-inch hex winding bars, 1/2 to 7/16 inch, part number 586. The hex shape is the big advantage over round bars because round ones roll right off your ladder tray the second you set them down. These stay put. The 18-inch length gives you decent leverage for lighter residential springs. If you are working on bigger springs or need more torque, look at the 24 or 36-inch versions instead. Make sure the 1/2 to 7/16 size fits your winding cone holes before ordering. Not all cones take the same bar size.