for punching out 10" records out of 12inch pressed records.
it is a special manufacured part, and must be used with a hydraulic press,
I don´t have much more informations, please check the pictures out here:
https://www.ebay-kleinanzeigen.de/s-anzeige/10inch-schneidmesser-fuer-schallplatten/2229163507-78-6407
diameter of the round knife is 250mm.
If you have questions, please ask
it is sitting in germany