In this video, Synthesizers.com’s Roger Arrick demonstrates his Q117 Sample & Hold, as part of their Thought Box 5U modular synthesizer.
The video is also a good demonstration of many of the potential uses of a sample and hold module, independent of brand and format.
The Q117 Sample and Hold module is used to capture a signal’s voltage level and hold it, so it can be used to control other modules. Sampling can be triggered by an external signal such as an oscillator, by the internal oscillator, or manually. An LED indicates when each sample is taken.
Details on the Q117 are available at the Synthesizers.com site.