It's Dave's version of a surge-protector. Non-sacrificial design, so sound quality won't degrade over time like MOV-based surge protectors. And also overbuilt in terms of clamping power, so capable of arresting pretty large surges. Run it right before one or more of his other power conditioning products, straight into the wall - to protect the system.
This is mostly true. I forgot the details of the design and emailed Dave. This was his response.
"Rob,
It does have MOVs in it, but they are there as a last resoert The spikes first hit gas discharge tubes, then avalanche diodes - THEN the MOV's. What this means is that only about 1 spike out of 10,000 will ever trigger the MOV. They are the fail safe for the entire system. Plus the MOVs are "next get" MOVs which are very, very quiet even after repeated hits.
Feel free to copy and paste this description.
My best,
<><
Dave"
I'm withdrawing it from sale for the time being as I reconsider if I really want to sell it.