These are new old stock surplus bulb sockets. The price is for a bag of 10x of these sockets. these most likely came from precision assembly company from way back when, as evidenced by the labels on the boxes (see picture). 

Orders will ship USPS first class; larger orders may ship USPS priority.

Our stock number 4403

We're a surplus store, and we aren't experts with most of this stuff.  So, we don't make any guarantees beyond what's stated in the listing & pictures.
Feel free to contact us with any questions!

DB