This is an adapter for VPI record cleaners that allow it to hold down 7" 45 RPM records. It should cover the label of most 45s. After printing you might line the bottom with some foam for extra sealing and protection.
I printed this on a Replicator 2 with .2mm layer height, 2 shells, and 10% infill. It took about 51 minutes.
The hole in the top should accommodate the threaded piece used to hold down 33 RPM records.
I messed up the dimensions on the version in the pictures so it doesn't quite cover the label. The scad and STL files have the correct dimensions and will completely cover the label.