Hareline Aluminum Sea Eyes. These Hareline Aluminum Sea Eyes are very cool gizmos to spice up our saltwater patterns. The aluminum is relatively light, but these babies are BIG and make a platform to glue in BIG EYES. Everyone knows that flies tied with big eyes attract big ocean predatory fish. Right-on. Why use aluminum, one might ask. Because we want the durability of a metal barbell fly tying eye without too much weight. Too much weight would make these sink too fast or would hurt us even more when we smack a fly into the back of the skipper’s head.