A six-function survival whistle — signal whistle, compass, thermometer, magnifying lens, signal mirror and a small LED light, all on one lanyard.

The step up from the four-function version. The additions that matter are the signal mirror and the LED: a mirror reaches an aircraft or a ridgeline miles away in sun, and a light reaches a search party at night. Between the whistle, the mirror and the light you can signal in almost any condition.

None of these replaces a dedicated tool. A real compass is better at navigating and a real headlamp is better at lighting a camp. What this does is put six usable signals on one lanyard that is always on you.

Hang it on a pack strap, a lifejacket or a jacket zipper.