Navigation
Navigation systems are important for being able to get in and out of the backcountry safely. A map and compass, as well as the knowledge of how to read them, are essential items for surviving in the wilderness. Topographic maps that show both trails and contours down to the 1000-foot level are best. The U.S. Geographic Survey topo maps are a good choice. Additional items can supplement them, such as an altimeter, for knowing your elevation, and a GPS unit. When using electronic items, check to make sure the batteries are fully charged before going into the backcountry.
First Aid Kit
While prepackaged first aid kits are commonly sold in outdoors stores, they often only have the basics, such as ibuprofen or aspirin, and small band aids. You should add moleskin to the kit for treatment of blisters, and a CPR mask for performing CPR and protecting yourself from bodily fluids. A SAM splint is a portable, moldable splint designed for field use that can be used to splint fractures. Carry 2-inch tape in the kit to secure the splint. Add 4-by-4 sterile bandages for stopping blood from major trauma. Carry some bandanas, which can serve as a sling for an injured arm. EMS shears are useful for cutting away clothing from an injury, and work better than a multitool.
Light
If you find yourself delayed while in the backcountry, either due to injury or weather, you may still be able to hike out if you can see the trail to navigate by. A headlamp should always be packed. Modern headlamps from Black Diamond and Petzl are very compact and light, yet throw a beam of light far enough to make hiking at night an option. Carry matches in a waterproof container so that you can build a fire if you find yourself needing to bed down for the night.
Nourishment
Water, food, and warmth can mean the difference between a comfortable night out and a night spent shivering trying to ward off hypothermia. Dehydration can cause you to have a decreased level of consciousness, leading to poor decisions. Carry adequate water on your backcountry outing, and bring a water filter or iodine tablets so that you can refill your water bottles from a lake or stream in the backcountry without getting sick from waterborne parasites. Carry extra food, particularly items high in carbohydrates like energy gels, energy bars, and GORP (raisins and peanuts). Carry extra clothing, such as a hat, Gore-Tex outerwear, and a fleece jacket to provide extra warmth if a storm moves in or you need to spend a night out. A space blanket is a lightweight item that can add warmth if you need to spend an unplanned night out.
Personal Locator Beacons
Personal Locator Beacons (PLBs) work by transmitting a signal at 406 MHz to satellites known as COSPAS-SARSAT (Search and Rescue Satellite-Aided Tracking), which then triggers search-and-rescue units. When you purchase a PLB, you must register it with the National Oceanic and Atmospheric Administration, which will then assign a unique ID number with your information to that PLB. Your personal information is sent when the PLB is triggered. Only use a PLB if you have no other options for self-rescue.