THIS GOES TO 127! is a MIDI velocity maximizer.
THIS GOES TO 127! is a simple VST with no controls. (The knob is just for show.) and it only does one thing, and does that thing very well: it makes all MIDI notes max velocity (127), regardless of input velocity. This makes the volume on playback max.
It's basically a dynamics compressor for MIDI. This is useful for heavy music, and/or for using inexpensive MIDI keyboards with poor touch. There are other ways of doing this, but none are as simple as using THIS GOES TO 127!