In the words of Old Blood Noise Endeavors:

Combining a three-control analog tremolo and a multi-shape digital tap tremolo, the Old Blood Noise Endeavors Whitecap tremolo lets the user find new tremolo textures by combining the two sounds in series or parallel. Quick chops, slow ramps, asynchronous modulations, smooth sines, phase flipped undulations, textural rhythmic drifts – its all there in the Whitecap.