From Mad Professor:

Silver Spring Reverb (SSR) is a compact, easy to use digital/analog reverb with a pure analog direct signal path. It creates a natural sounding ambient reverb that will not get in the way of your original signal.

The SSR’s sound is exceptional with a clean signal but was specifically designed to work equally well with the tougher performance requirements of distorted tone. The SSR can be used before distortion, although it was primarily designed to go after. If you use the SSR before distortion, you may want to use a lower Reverb (Wet/Dry) setting.