This is a filter plate for the head of an Atomic type coffee machine. Also included are 4 brass screws- two long and two short (these screws will fit the majority of vintage Atomic type machines- however the thread and screw length varied over time and in some cases these screws may not fit your machine.
Alternate screws can be found at fastener/hardware outlets. The filter plate can be worn out on older vintage machines and replacing it will improve performance. Brass screws are much better than the steel ones which can rust and jam.