Potter & Brumfield Baby!

[SoundTech-LG]

I guess they may not break much. But what beauties they are!
Behold!

https://www.ebay.com/itm/255409247109?itmmeta=01J3KEG8R76Q545SCPF92SFK3A

P&B's history may be traced to 1932, when Elbert E. Potter and Richard M. Brumfield established a small manufacturing business in their hometown of Princeton, in southwestern Indiana. At the time, the two young men were employed at the local Hansen Manufacturing Company, which produced small motors for clocks. There, Potter was a toolmaker, and Brumfield, who had studied engineering at Purdue University, worked in the design and drafting department and also operated a die cast machine. During 1932, however, both men were often out of work, as the company was forced to lay off large numbers of its employees in order to withstand the effects of the Great Depression. During these periods of unemployment, Potter and Brumfield decided to try developing a business of their own.

[BILLPOD]

Why are these switches so expensive?......is it because they are old and rare?
or because they have phenomenal specifications?   Uncle Google doesn't tell me much, other than they are available on E-Bay?

[Stray Electron]

  I tried to buy some of the P&B Time Delay relays in the late 1970s and they were about $40 at that time!  And they weren't the fancy ones like these. They were just a fixed delay time. I needed about 8 or 10 of them but when I found out the price, I gave up on that project! 

   But I've seen a lot of very nice P&B Time Delay Relays in mil surplus equipment over the last 30 or so years and at $159 each, now I wish that I had saved them and put them on E-Greed! 

[TimFox]

I bought some P&B  CUF-42-70120  relays from a surplus dealer years ago.
They use a mechanical DPDT relay ("plate relay" type) operated from 120 VAC through a unijunction-transistor R-C timer with external timing resistor.
I had a few of them fail due to the tantalum timing capacitor, which I replaced with a lower value higher voltage unit that fit into the enclosure.
When I tried to purchase more, the original dealer was out of stock and the new price was much too high for me.