Rocky Mountain V.E.T.T Mouthpiece Enlargement Ring - This enlargment ring simply snaps over an existing V.E.T.T. mouthpiece to bring the diameter from 1 inch to 1 1/2 inch. Snaps over an existing V.E.T.T. mouthpiecefrom 1 inch to 1 1/2 inchAlso fit the Threat and Wild Frenzy Grunt Tubes