NDūR's Lensatic Compass with Whistle is great for anyone's survival bag to help one if the situation arises where they are separated from their group, lost their way on the trail or find yoruself in a dire drastic survival situation.Features: Plastic ABS Housing Liquid Filled Whistle Bezel Ring Floating Luminous Dial Rear Sight w. Lens & Lighting Slot Weight: 2.21oz Dimensions: 3 x 2.2 x 1.34