urrth is an Amp Simulation.

Use your own effects in front for a solid-state clean jazz vibe or throw in a distortion pedal to bring out the true character. The amp is naturally bassy and the M (middle) dial seems to give the most audible affect on the sound when cutting/boosting. There is a bit of compression built in so that when pushing the amp too hard it will squash the sound rather than give you those ice-pick highs. There is no cabinet simulation so you will need to use your own (IR) loader.

muun is an Overdrive Pedal Simulation that "has a mind of its own".

The push knob will add gain to your signal and when rotated clockwise will add a subtle chorus effect which adds some dynamics to your string attack through your chosen amp. The pull knob when at its lowest value will give a lo-fi character to your sound, and when rotated to maximum and in between will bring your sound closer or farther in tonality. With both knobs near their 12 o'clock positions (maybe even touching the smaller dotted orbit line) the pedal offers a nice vibe to your amp keeping the sounds in peaceful orbit.

praamp is a guitar pedal simulation.

Throw it in front of your favorite amp to give it a jolt. A simple tone knob either lightens or darkens the sound, while the boost knob pushes the amp into its sweet spot. Dime the knobs for an all out assault, or use the power judiciously to sculpt to your flavor of overdrive.

spaank is an amp simulation.

Small and mighty, this amp offers a fixed mid voicing yet a very responsive bass and treble EQ. Keep the drive and volume low for cleans, or push both to taste the dirt. This amp also responds well to pedals allowing you to shape the tone to your own.