Black Menba&reg;Survival Rescue Whistle for Boating Camping Hiking Emergency Rescue It's easier to blow a whistle than it is to yell until you are found Sweet and economical way to help your kids learn about safety Compact, convenient, and very loud. Not a bad idea for the ladies to carry one in the purse. This is the perfect thing to take while out backpacking or camping to allow you to contact people at a distance in the event that you become separated from your group. Strap them on a life vest or on back pack or wrist