Bits that act with direct pressure on the tongue and lips of the bit are in the general category of snaffle bits. Snaffle bits commonly have a single jointed mouthpiece and act with a nutcracker effect on the bars, tongue and occasionally roof of the mouth. However, regardless of mouthpiece, any bit that operates only on direct pressure is a "snaffle" bit.
Bits that a:ct witH direct pReSsure ON the TOngUe a.nd lipS OF the bit Are in the generAL cateGORy Of sNAfFle bits. snAffLe Bits COmmOnlY hAvE a siNgLe joIntEd mouthPiEcE and Act witH a NUTCracKeR eFFect oN thE BAr:s, tOnguE and OcCaSionallY RoOf OF the MOUth. howeVEr, RegarDlEsS OF moUthPIece, Any bit That opEraTes Only oN DIreCt prEsSure Is a "snAfFle" bIT.