This appears to be an emulation of Ibanez’s Tube Screamer, and is designed to be used before your amp simulation to give you a tighter low end and add a bit of boost to lead parts.
Download: Win VST 32/64bit | OSX VST Universal Binary | OSX AU Universal Binary
Minimum requirements: Intel CPU (w/SSE2) | 32 Bit / 64 Bit Windows XP / OSX 10.5