A 16 MM shell with stainless steel bracelet would have a striking and bold appearance. The large shell beads, at 16 MM, would add a natural, oceanic element, while the stainless steel would provide a modern, sleek contrast. You could alternate the shell beads with stainless steel spacers or have the shells as the main focal points, with a stainless steel clasp or accent pieces to add durability and style.
This combination would create a blend of organic and industrial elements, perfect for a unique accessory. Would you like a specific color or type of shell, or any additional details?