DIY Jewelry Making: 12pcs Brass Clasps for Bracelet Making with leather cord, Platinum color Size: about 4mm wide, 15mm long, hole: 3mm. SILVER Color Brass Screw Clasps, Column, Silver Is used for 3mm round leather cord to make bracelet bangle. Tiny, but strong. Ideal for light and medium-weight necklaces. For best results, slide clasp ends apart to keep magnet from loosening.