3 1/8" Silver Whistle and information holder with a 1" key ring. It has a loud, crisp sound that attracts attention, a space inside for emergency information and it's sealed with an oring gasket. For sports, hiking, boating, camping, hunting, emergency survival, rescue, etc. Children can signal danger or location if lost. A whistle requires little effort to use even if injured. It's sound carries better than yelling and doesn't go hoarse like your voice will.