They say:

The first stock Henretta 2in1 pedal, the TREMBLETANK is the ultimate utilitarian companion for your rig.  Get a wide range of reverb sounds, from snappy spring-ish to lush halls, and amp-like bias-based tremolo in one compact pedal.  Use the effects individually or together.  The toggle switch flip-flops the order in which the effects feed one another for added versatility.