The Guitar support Back strap allows you to add a back strap to an additional guitar or bass, giving you the freedom to quickly switch between instruments. The non-marring guitar support Back strap attaches to the instrument's strap pins and offers 12 side-to-side adjustment positions so that you can find the perfect balance point of your instrument. Once achieved, simply hook the harness (sold separately) to the back strap. When finished playing, unhook the harness from the back strap. The guitar support Back strap can be left on the instrument as it fits easily in your case. This revolutionary system really enhances your comfort level while playing for long sessions.