Gatecomb is a stereo comb filter. The frequency of the comb filter is controlled by an AHDSR envelope which is either triggered in sync with the sequencer or by the the incoming audio reaching a certain threshold.

There is also a filter to control the sounds (which can sometimes be very brutal). When it is processing a stereo track, the right filter can be offset by octaves or semitones.

Gatecomb is a stereo vst effect. It will work on mono channels but the right comb controls will have no effect.