Puritan PSM156

Can someone explain how the "non-sacrificial gas surge protection" works on the Puritan PSM 156?

If there is a surge, does it shut your components down. Then what happens?

Also, what is the small black button located near the power cord inlet used for.

Thanks for the information.

anyone gone from psm156 to niagara 3000/5000? I've read differing opinions; some prefer the Puritan whereas others say the Puritan makes music sound thin/bright and prefer the niagara 5000. I'm currently using Lab12 Gordian and Niagara 1200, both of which I quite like, but am curious of the benefits/bump in sq of going to Puritan or 5000.

My PSM156 arrives tomorrow, along with an Ultimate cable.

Not sure why this is in the cable sub-forum, but anyway -I did plenty of reading before upgrading my power conditioner, here are some good reads: I bought the PSM156 and am extremely satisfied with the improvements

PSM136/156

Niagara vs PSM

I have the Puritan 136, which I found made an immediate positive impact on my system. I am planning, at some point, upgrading to the 156 in my main system and using my 136 in my secondary one. 
 

I am curious about the ultimate cable versus the classic one which I currently have. I’m interested in making that upgrade too. 
 

Can anyone share their experience with Ultimate cable?