No pecuniary interest in any of these, just found the prices attractive after being high for about a year.
On ebay lot of 25 pcs NOS mercury wetted reed relay for $35.
https://www.ebay.com/itm/264947307881Pretty much giving them away.
coil 12VDC
Contact 1000V 2A
MTBF 2000x10^4 cycles (@1V/10mA)
CP Clare CUPP001A512
Mercury wetted reed relays are excellent for signals in tube equipment where CMOS switches can't handle high voltages. The contacts never tarnish so even tiny signals come right through and are without the electrical noise that dry contacts often make opening and closing.
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Large Mercury contactors handling many tens of amperes @ 120/240/600VAC. Never burn a plate relay again. Ya just can't have too many of them!
A 30A 600V double pole unit is $16.
The ebay search finds these big contactors:
https://www.ebay.com/sch/i.html?_from=R40&_nkw=mercury%2B%28contactor%2Crelay%2Cwetted%29%2B%2810A%2C15A%2C20A%2C25A%2C30A%2C40A%2C50A%2C60A%2C70A%2C75A%2C90A%2C100A%29&_sacat=0&LH_TitleDesc=0&_sop=15