18ct Gold 750 Hallmark, these bolt rings are just the ideal thing for jewellery making and clasp repairs. 
Available in 3mm (external diameter) with open "tail" tail loop for easy joining to a chain.
A clasp made from 18ct Gold.
Stamped "750" - 18ct gold.
Measurements - millimetres 3mm  (external dimension)
Fitting : Bolt ring closure with open eye.
Stamping : 750 / 18ct