Gently used Seymour Duncan power stage 170. Only really used for rehearsal a handful of times.
It provides a great clean preamp platform and high-headroom amplification. Because of this, it is highly favored by players who use digital modelers (like a Line 6 Helix, Quad Cortex, or Kemper) or complex analog pedalboards, and want to push air through a standard speaker cab on stage rather than relying on a direct-to-FOH or a standard combo amplifier.