Bolt On Wheel Cover Conversion Kit Mud Cover Installation Kit, Screw-In Inserts / Rivets Included, 1-3/8'' Spring, Kit popular Kit For Use On Most Weld And Aero Wheels. Kit Includes: 3) Insert Plates, 3) 1/4'' Bolts, 6) Rivets Approved For World Of Outlaw And Lucas Oil Series thread 1/4''-20 threaded Inserts Included yes threaded Inserts Quantity1 Bolts Included yes bolts Material steel bolts Color black bolts Finish paint bolts Quantity1 Rivets Included yes rivets Material steel rivets Color zinc rivets Finish plated rivets Quantity 2 Springs Included yes spring Length 1-3/8'' material steel color zinc finish plated quantity kit