The Stealth Tune guitar strap with embedded tuner doesn’t plug into the guitar but uses resonance transducer technology to assess tuning from vibrations transmitted by the instrument it is attached to. As it doesn’t rely upon an audio tone, this allows tuning of both acoustic and electric guitars and basses even with the volume off, while using local resonance avoids any danger of crosstalk from other instruments. The inclusion of a backlit LCD, lighting red for out of tune and blue for in tune, is said to allow use of the system on stage, in the dark and even while playing.