In the words of Strymon:

There is something uniquely powerful about the sound of a vintage rotary speaker system. The organic chorusing as the treble horn and bass rotor start speeding up. The grit of the internal tube-driven amplifier, creating additional harmonics that spin around the room. Plug into Lex, close your eyes, and be transported by this classic sound, recreated with astonishing realism and depth for your pedalboard.