VTL Series Linear Pneumatic Piston Vibrators provide quiet linear vibrating force using an air cushioned piston. Frequency and amplitude can be controlled independently – frequency is controlled by varying air pressure and amplitude is varied by changing the weight of the vibrating mass.  The VTL Series Vibrators can be mounted by the piston or by the housing; therefore, either the piston or the housing can be used as the vibrating mass.  Additional weights can also be added to the free end of the vibrator, further increasing the range of available amplitudes. Using additional masses the vibrator is able to work at low frequencies down to 15 Hz and to generate large amplitudes.  VTL vibrators combine the advantages of low frequency rotary vibrators (large amplitudes) with those of magnetic vibrators (adjustable amplitudes). Additionally, they have the advantage of being able to select the most suitable frequency to obtain optimum results. VTL's are effective flow aids for feeders, tables, screens, and hoppers.