Snoring devices work by holding the lower jaw and tongue forward and away from the back of the throat. The space behind your tongue is increased when the device is in place and this makes it less likely to vibrate and create the snoring noise. The device fits over the teeth snugly and is used just at night. In their simplest form they consist of gum shields rather like those used by rugby players or boxers, for both upper and lower teeth (Negus). More recently available are separate top and bottom halves that clip onto just the teeth and allow for some adjustment of the degrees of lower jaw protrusion (Thornton).