Cufflinks by Josef Koppmann Stunning 24ct gold and silver cufflinks with large opals. The cufflinks are handmade using sterling silver. The opals are set into solid 24 carat gold and a hinged bar, soldered on the back of the square, snaps securely into place when worn. Features Primary Material : 24ct gold and sterling silver Other Materials : opal Fitting Type : hinged bar Dimensions (mm) : 18x15x6 One of a Kind : Yes Metal : 24ct gold and sterling silver Gems : opal Hallmarked : Yes Cleaning InstructionsThe cufflinks are best kept clean by rubbing and brushing them gently under running water with bicarbonate of soda. Do not submerge in water for long periods and do not clean the cufflinks in ultrasonic cleaning systems.