Copper alloy, 7.15 grams, 21.03 mm. 1st Century A.D. A circular disk with a bordered circumference of niello, with that is an inner circle composed of triangular niello, around diamond sections of silver inlay. Protruding from the centre is a long expanding knob/nipple. The reverse of the piece has a rectangular section, which the belt would have been fed through. Very Fine condition.