20x20cm Square Photo Mount for IKEA SKATTEBY Frame with Window cut at 6x6 inch
SILVERHÖJDEN, DALSKÄRR, VIRSERUM, EDSBRUK, LERBODA, LOMVIKEN, UBBETORP, SKATTEBY, KASSEBY & RAMSBORG. Use a search engine to convert one to the other if you are not sure. It is a Bevel Cut Aperture.