Art Deco Krementz Platinum & Gold Filled Inlay Rim Cufflink Set Black Enamelling. Comes with original box which you can see in the pictures isn't great inside as it appears to have some wear and tear inside and dirt marks. I haven't attempted to clean it as the item is from the 1920s / 1930s and almost 100 years old so I don't want to cause further damage. One of the shirt pins is unfortunately missing so it isn't a complete set. One of the cufflinks does have some damaged on the black enamel - please study the pictures!
With some research I've done people do think the black material is onyx - so I've described the item as best as I can to my knowledge as I believe it is black enamel.