The SOS Hand Horn and Gas Kit is a fantastic survivalist item and is definitely the most effective way to signal for help if you're off the beaten track and lost or in distress. Simply attach the horn to the gas bottle and trigger to release a loud alert sound.
Pro Tip - Learn the SOS morse code sequence and use it with this horn to alert help
". . . _ _ _ . . . " - aka, 3 fast alerts, 3 slow alerts, 3 fast alerts