While there are hazards specifically associated with solo diving, most of these can be planned for and their consequences mitigated by the use of appropriate equipment. In technical diving, where redundancy of critical equipment is standard policy, self-sufficiency is emphasised and taught more extensively than in recreational diving. This philosophy should also be followed by solo divers. A solo diver operating beyond the range for acceptable risk for a controlled emergency swimming ascent needs to carry a second, independent source of suitable breathing gas, which includes a regulator and preferably a submersible pressure gauge. This emergency gas supply typically takes the form of a pony bottle, or for more demanding diving, a twin tank set with the capability of independent operation of each tank. Additional equipment carried may include a backup dive computer, a backup dive light and a backup dive mask. The diver must be familiar with the equipment configuration used and be able to access the equipment easily if it is needed. A solo diver needs to be particularly aware of overall personal fitness and health and the limitations it may impose on their ability to manage an emergency. Finally, the solo diver may dive a more conservative dive plan than he or she might dive with an equally competent buddy diver.