Sterling Silver 2.55mm D/C Square Franco ChainProduct Details Material; Primary Purity 925 Finish Polished Length of Item 18 in Chain Length 18 in Chain Thickness 2. 5 mm Chain Type Franco Chain Width 2. 55 mm Clasp Connector Lobster Clasp Thickness (Female end) 1. 9 mm Clasp Thickness (Male end) 2. 7 mm Clasp Width (Female end) 3 mm Clasp Width (Male end) 4. 3 mm Coating Anti tarnish Feature Solid Manufacturing Process Casted Material; Primary Sterling Silver Item Weight U M gm Width of Item 2.