Acrylic Mounted Jewel Studs. These plastic jewels are mounted in a ring stud. Held tight by prongs so it is complete and ready to apply. Stud Description outer ring diameter: 12 mm (1/2 inch) inner ring diameter: 10 mm (1/3 inch) base to tip height: 7 mm (1/4 inch) prong length: 8 mm (5/16 inch) color of ring stud: silver material of ring stud: brass with nickle plating jewel color: clear - transparent jewel material: acrylic shape: high cut dome jewel