The XQP 541 Optical Compressor is a feed-back style device producing very smooth and unobtrusive gain reduction. A Silonex optocoupler controls gain and results in natural attack and release. The ratio is around 3:1.
A full ten-segment gain reduction meter works in the subtractive style of the old VU models. The resolution starts at 1dB per segment at the top and becomes broader towards the bottom.