5/8" X 1/2", and are not marked.
eBay
3/4" X 5/8", and neither are not marked.
eBay
1" X 1/2" at their widest and are not marked.
eBay
3/4" X 1, and are marked with a Pat. No. 2920363, as shown in photos. These may need a good cleaning / polishing and may have age appropriate wear!
eBay
It has a grey color but pearlized like abalone.
eBay
Enamelled Cufflinks Used Good condition - few very minor marks. In original case (surface scratches to case outer See pics) Approx size to cufflink front 0.5x0.75"
eBay
3/4" and are not marked!
eBay
There is an odd mark on the back of the cufflinks, sorry I do not know what it is nor can I get better pics!
eBay