Good working variable filter, still hase the two battery packs installed inside. I had to disconnect them due to age and small amount of corrosion on two terminals. These terminals were on a seperate terminal post and the corrosion did not get onto the switching components. Comes with the power cord.
The 3323 Variable Filter is a solid state, variable dual-channel electronic filter that is digitally tuned over the range from 0.01Hz to 99.9kHz.