Cufflinks by Josef Koppmann The cufflinks are handmade with Sterling Silver. A hinged bar, soldered on the back snaps securely into place when worn. Features Primary Material : silver Other Materials : pyrite Fitting Type : hinged bar Dimensions (mm) : 22 x 11 x 12 One of a Kind : Yes Metal : sterling silver Gems : pyrite 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.