Found this on the beach and by the look of it it's been in the surf for a long time. Any idea of its age? From the wear I'd guess its been in the water at least 50 years.
Cool! That's a cateye. Hard to see the details inside but by the shape of the red inside it's probably either a Japanese cateye or a Peltier banana. That would probably make it a safe bet that it's from the 1950s-60s, possibly 70s, but not 100% because companies have made cateyes since the late 40s or so up to today.