For the BAW device, or more specifically an AT cut Thickness Shear Mode (TSM) device, we can see that the thickness shear vibration is in the plane of the crystal plate with the maximum displacements occurring on the crystal faces. This is ideal for sensing application and because there is no vertical component of displacement, the BAW device can be used for liquid-based applications without experiencing excessive damping. TSM devices are sensitive to mechanical and electrical properties occurring on their surfaces. For mechanical properties, they are sensitive to mass loading and visco-elastic changes like stiffening and softening. For electrical properties, the devices can be sensitive to any property that interacts with the electrical field that is coupled to the acoustic wave. This effect has been given the term electro-acoustic interactions. For TSM devices with solid circular conductive electrodes, the effects due to electrical properties of the fluid are minimal. Because of this fact, TSM devices are not typically used for measuring electrical properties unless a modified electrode is implemented.