Boutique compression and limiting.
The dyna-mite is the workhorse of the Valley product line. It was designed to solve problems during tracking and mixdown. In its peak limit mode, the dyna-mite could respond to transients in around 6 microseconds, while in the average mode, the integration time was closer to 10 ms. This doesn't mean it took 10 ms to respond to transient information, it just allowed some of the fast rising waveforms to pass through while it integrated them in order to adjust its gain.
The result is a really fast limiter that doesn't "squash" the processed program, or a very unobtrusive average limiter that could perform 20 or more dB of gain reduction without producing large amounts of objectionable dynamic distortion. There is gain recovery coupling in the control, so it works as a high ratio compressor when the threshold is adjusted down below 0 dB, which is its nominal rotation point.
As an expander and gate, the dyna-mite is exceptional due to the presence of the auto-release circuit, which was originally called Anticipatory Release. This circuit prevented the release circuit from interfering with the attacking portion of the control waveform, yet was capable of very fast release times when the device was not being called on to open up to unity gain by a rising signal wavefront.