Bulk Pro Systems Model TF Tuning Fork Level Switch is ideal for level control of powders and fine grained solids, especially those with low bulk densities. The TF incorporates a piezoelectric crystal that vibrates the fork at its natural frequency. When the fork comes in contact with material the vibration is dampened and the switch changes state. As the fork becomes free of material the switch changes back to its normal state. Featured in the TF is user selectable fail-safe operation of the contacts. This unit is not affected by vibration from conveying systems, motors or the movement of material. It can be mounted in any position and is available with factory built extensions for mounting on top of the storage vessel.