The JetScream™ Whistle by Ultimate Survival Technologies focuses blown air through harmonically tuned chambers to create a piercing shriek audible over most other natural and manmade noises. Due to its pea-less design, it even works when wet, making it the perfect accompaniment to all outdoor activities near rivers, lakes, or oceans. Flat enough to fit in your pocket and attached to a lanyard, it is just as useful in the city as it is in the woods. It measures 2.25" long x 1-3/8" wide x 1/2" thick, and weighs only 3 oz. Available in orange with black printing or black with green printing.