One of the rarest Soviet pedals, ever... 

It's the greatest old soviet overdrive & compression\limiter pedal, Elektronika Compression/Sustainer made in 1982 year by one of the biggest USSR music equipment brands - "Elektronika" (famous for its Elektronika EM-25 synth, EM-26 Vocoder, FL-1 Flanger etc).

The pedal is fully functional. Maintenance done, jacks replaced.

The pedal is powered by a battery and a 9-12V power adapter with a plus in the middle.

Sound: I would characterize this as hard compression, which levels out your signal to a certain level. with a clean signal and overdrive control, and a second sustain control. It is advisable to use this pedal in addition to your pedalboard of other effects. No modifications were made to the original scheme. Exclusively replacement of electrolytes.

Inside the case there are two trimming resistors that are responsible for adjusting the compression level

The pedal is very cool, it helps your guitar or bass fit perfectly into the mix, and also makes the guitar more expressive in the mix.