OVNIFX.com

Specifications:
Input impedance 1 MegOhm
Output impedance 1 kOhm
Power supply 9V DC, center-negative plug (standard size)
Current draw 16 mA max
Size 62 mm x 112 mm x 50 mm
Weight 400 g
Easy-access battery door in base plate.
The footswitch is a relay-based true bypass.
The pink LED indicates when the compressor is switched on.
The orange LED indicates when your signal is being compressed.
When you first plug in, it is normal for the orange LED to come on and stay on for a couple of seconds.
The Thresh switch engages a -20 dB pad on the input of the compressor sensor, to reduce overloading from very high-output instruments.
The Sust knob controls a gain stage going in to the compression circuit, so it affects both threshold and ratio together. Higher settings mean a lower threshold and a higher ratio.
The Attack knob actually controls both attack and release times. Turning the knob clockwise gets a slower attack and a faster release. Counterclockwise settings will be smoother, more fluid, while clockwise settings will be more percussive.
Range of attack times: approximately 1 mS to 100 mS
Range of release times: approx 100 mS to one second
The Level knob controls the volume of the compressed signal.
The Blend knob controls the volume of the dry/uncompressed signal.
The Tone (EQ) section only affects the compressed signal, not the dry signal.

Here is a graph of the frequency response, with the tone knob set at noon, using a white noise source. The green line is bypass, and the blue line is with compression at maximum:

Frequency Response Graph

This graph shows the range of effect of the Tone knob:

Frequency Response Graph