I collect antique cufflinks that are double-sided or snap type. The double-sided ones are usually connected with a chain, bar or some other type of mechanism to hold them together. Snap ones are held together by the snap mechanism. But as the pair in the bottom left of this picture indicates, pairs were made with both of these closures at once. As a collector, I have only ever seen this type of manufacturing in several other pairs, in the thousands and thousands of pairs I have seen in my hunt for cufflinks. These may well be my favorite pair (well, unless until the next pair I acquire.................) Anyone else ever see ones like these?