Flat Disc Back - (Front Fastening) Flat disc base is fixed, the gem top unscrews, bar length is 6mm or 8mm, bar width is 1.2mm with a 3mm or 4mm gem top. Ball Back - (Back Fastening) Plain back ball fastening, gem top is fixed, does not unscrew, bar length is 6mm, bar width is 1mm or 1.2mm with a 2mm, 3mm, 4mm or 5mm gem top.
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