Rarest devices you’ve seen or bought off of eBay

What was the rarest devices you have seen or bought of eBay

I didn’t buy it, but it was a Christmas gift.
Simplex 4251-30
I also bought my Siemens u-ec-mcs from eBay.
They have good rare devices for a somewhat reasonable price. (I actually saw some truealert chime strobes listed.)