Carrying a whistle while swimming outdoors allows you to attract attention, should you get into difficulty.  The Acme 649 Survival Whistle can be attached to your tow float or your swimming costume, incase you need to alert someone or call for help. Made in the UK, using shatterproof plastic, the Acme 649 whistle is easy to blow with minimal effort, giving a discordant note, which is loud and attention grabbing.