New vintage spring closure hoop earrings

New vintage spring closure hoop earrings 18 mm diameter, 6 mm wide Very pretty and light metal. 5 petal flowers (pointed and rounded) and leaves. Unusual spring back closure for non-pierced use. It doesn’t screw on. It’s a spring mechanism. Unless I’m doing it wrong! My ear was too fat to fit comfortably but I also never wear any earrings! I’m not sure how to adjust it, if it’s adjustable. New, never worn, vintage c. 1970s. Probably costume, Casted goldtone metal. Hallmark: PAT PEND. On original manufacturer’s packaging (brown velvet).