Lindell Audio 7X-500VIN Single-Channel Vintage Edition Compressor/LimiterThe 7X 500VIN Single Channel Vintage Edition Compressor Limiter from Lindell Audio fits all 500 series compatible power supplies. It features a high pass sidechain filter that allows you to focus the unit's response. It features 3 way switches that allow you to set the compressor's attack, release, and ratio. With Mix Knob, you can mix dry and wet signals (parallel compression). 500 Series format compressor FET based technology Variable mix control