I know these companies build their surge suppressors with similar technology, and that Zero Surge holds the patents and OEMs for Brickwall, etc. Not sure if they OEM for SurgeX or just licence to them. Anyhow, I was concidering getting a 20A NEMA panel model, and didn't have enough info to determine why it might be better to spend extra on the SurgeX over the Zero Surge panels. I read on one site that SurgeX improved the technology for audio, but I have no facts on that to justify the extra expense. Does anybody know if there are significant differences between them?