Product DetailsSignal + Central aiming hole1. Hold mirror by one hand， with mirror plane aiming at light source. Let light ray reflect on the other palm.2. Keep this relative position and move aiming hole to your eye. You can clearly see a bright spot through this hole. This spot is named sight bead.3. Slowly waggle signal mirror to let the sight bead overlap communication goal. Then the goal will exactly see heliogram you are sending.4. Move sight bead?��s two points back and force along horizon when you cannot see the specific communication goal. Then the heliogram will be seen dozens of kilometers away even on a foggy day.FlintstoneA 4.5cm long flint is inlayed on the back of the upper left corner. Convenient for emergency use， providing fire source for outdoor activities.Note: Scraper is not included.Noctilucent compass:A compass is inlayed on the back of the lower right corner that helps to find general direction in outdoor. (Not professional compass， there will be a slight deviation in precision)RulerThere are some short range ruler and measuring scale on the back which can be used to measure things. Whistle + LanyardWhistle is designed as pendant. You can blow it in emergency. Very convenient and practice.Size: 120 x 78 x 10.5 mmFunction: signal mirror， high frequency whistle， compass， flintstone， ruler Photo May Slightly Different From Actual Item in Terms of Color Due to the Lighting During Photo Shooting or the Monitor's Display.We have some creative products， please visit our store to see selection. Visit My Wish Store: lcmqstore