We call this a “comfort gag” because the mouth pieces can be carefully trimmed to fit and after inverting the gag and dipping it in hot water and put into the mouth (CAREFULLY) it will mold to the wearers mouth.  It is not restrictive in the sense that it doesn’t HOLD your mouth open it stuffs your mouth because the mouth pieces close in on the tongue.

We know this gag, because we designed it and we use it.