Tone-Gard is designed to isolate the back of a mandolin from the player's body, producing more volume and enhancing the tone.
You can test the concept right now without a Tone-Gard. Play your instrument normally, while facing a wall about a foot or two away, allowing the sound to bounce back directly. After you are used to the sound, hold the mandolin by the neck so that the back of the instrument is a couple of inches from your body. Now try playing a few chops. Go back and forth, against and away from your body and you will notice a difference. You will hear a difference just hitting one chop and letting it ring while holding it against you, then away from you.
An additional benefit is to protect the back of the instrument from wear, dings and scathes. You can and should leave the Tone-Gard on the instrument all the time. It fits in most cases, including Calton.
