I have 6 of these units for sale.

The ACL2 Pro from Alto is a dual channel compressor/limiter/gate that features several innovative circuit designs. The compressor attack and release times can be automatically set dependent on the source material, or full manual control can be exercised.
The unit can function as either 2 separate processors, or stereo linked to provide real stereo compression. An adjustable expander/gate and very low distortion Voltage Control Amplifiers (VCA) deliver smooth sound.
A sidechain function allows the ACL2 Pro to be placed in an external effects loop, while a second, internal sidechain employs a switchable low-cut filter to help control pumping due to heavy low frequency content. LED meters on each channel display gain reduction and input/output levels.
Dual channel compressor/limiter/gate
Includes auto attack and release times based on input signal analysis
Also includes user adjustable attack and release times for full manual control
Smart Knee Control Compressor (SKC) delivers a "soft knee" compression envelope with lower compression thresholds, and changes to a "hard knee" function with heavier compression
Smart Ratio Control expander adjusts the expansion depending on the input signal so that signals slightly above the noise floor level get the major benefits
Smart Gain Control peak limiter activates above a certain user adjustable threshold to radically restrict signal peaks
Couple Switch engages stereo mode operation where channel 1 becomes the master channel and overrides all the controls and switches of channel 2, with the exception of the SC Monitor, SC External, SC Filter and Bypass switches, as well as the Peak Limiter control
Sidechain send and return connectors allow for placing the compressor in an external effects loop
A switchable low-cut filter on an internal sidechain removes bass signal from the compressor circuit thus minimizing audio program pumping triggered by for example, a bass drum
Gain reduction LED
Switchable input/output level LED meters