This group stresses being able to stay alive for indefinite periods in life-threatening wilderness scenarios, including plane crashes, shipwrecks, and being lost in the woods. Concerns are: thirst, hunger, climate, terrain, health, stress, and fear. The rule of 3 is often emphasized as common practice for wilderness survival. The rule states that a human can survive: 3 minutes without air, 3 hours without shelter, 3 days without water, 3 weeks without food. 
Radio transceiver, standard VHF marine when operating near inland shore, 121.5 MHz AM VHF guard channel capable aircraft band transceiver to contact rescuers and high overflying commercial and military aircraft visible by contrails, an optional amateur radio if a licensed radio amateur, (see Ham Radio) or an AM/FM/Weather/Shortwave radio receiver to receive precise time for celestial navigation as well as weather information
Survivalists maintain their group identity by using specialized terminology not generally understood outside their circles. They often use military acronyms such as OPSEC and SOP, as well as terminology common among adherents to gun culture or the peak oil scenario. They also use terms that are unique to their own survivalist groups; common acronyms include:
Common preparations include the creation of a clandestine or defensible retreat, haven, or bug out location (BOL) in addition to the stockpiling of non-perishable food, water, water-purification equipment, clothing, seed, firewood, defensive or hunting weapons, ammunition, agricultural equipment, and medical supplies. Some survivalists do not make such extensive preparations, and simply incorporate a "Be Prepared" outlook into their everyday life.
Another concern when you’re lost in the wild is where to procure potable water. Sometimes there will be bubbling streams of crystal clear water rolling down wooded hillsides to fill your water bottle and sometimes you’ll have little more than a stagnant pool standing between you and dehydration. The LifeStraw Personal Water Filter is survival gear that can turn that stagnant pool into a lifesaver.