According to Wikepedia, the use of the Ichthys symbol by early Christians appears to date from the end of the 1st century AD. It refers to a symbol consisting of two intersecting arcs, the ends of the right side extending beyond the meeting point so as to resemble the profile of a fish, said to have been used by early Christians as a secret symbol and now known colloquially as the ";Jesus fish" and (to a lesser extent) the ";holy mackerel".
Dimensions: 22mm x 10mm (approx.) Weight per cufflink: approx. 6g (medium)
Size = x mm (W x H)