Installation is as simple as installing and tightening the bolt, then tightening a small set-pin. The set-pin in the bolt expands the bolt threads against the thread wall providing an unmatched lock. No clips, small wires or other small pieces to go flying to the dark side of the engine compartment either. As always, Percy’s Split-Lock fasteners are made and packaged in the USA (not China) using only premium quality materials. Sizes are available for most all engine applications. Quit leaving your header bolts on the highway or race track by contacting your nearest performance retailer or Percy’s High Performance at (573) 346-4409 www.percyshp.com