CMC Fox 40 Whistle
Without a “pea” that will stick or swell when wet, this whistle works under almost all conditions, including under water. The Fox 40 has a reputation for being one of the loudest whistles made. Its plastic body will not rust or transfer cold like metal whistles. It can be attached to your PFD or Radio Chest Harness to keep the whistle close at hand, but out of the way.