Easy Hinge Click Price Per Piece No Tools Required Material: 316L Surgical Steel Most popular size would be the 8mm length which is not too big and not to small. It provides a little bit of breathing room and fits comfortably. Thickness: 18ga(1mm), 16ga(1.2mm), 14ga(1.6mm), 12ga(2mm), 10ga(2.5mm); Bar Length: 5/16"(8mm), 3/8"(10mm), 1/2"(12mm), 9/16"(14mm), 5/8"(16mm)