Be sure to pack this survival tool whenever you venture out. Make sure each child in your group has one in case they become lost. The whistle sound is a universal call for help! Can be used by referees for all kinds of sports. In the event of an attack, it can often scare away a would be assailant. Size: 2-3/4" x 1". Two inch key chain. Black durable plastic. Three separate tones make it easier for anyone to hear it. Light weight, thin profile so it packs easily into your backpack, pocket or purse. Stock up. Give one to each child and adult in your group. Keep one in each car or truck. Give them to your grandchildren. Great stocking stuffers.