The Road King kits are designed to deliver an exceptional sound experience while retaining as much interior bag space as possible. The RFK-HDRK amplifier mounting kit is designed for use with the Rockford Fosgate Power TM400X4ad 400-watt amplifier (sold separately) and is supplied with the complete plug-and-play wiring harness. Designed for use with 1998-Current Harley-Davidson Road King Motorcycles.