one of these three classes occupies a vehicle (with the exception of the recon), nearby personnel and vehicles can be replenished, repaired or healed by being in close proximity. Assault - Primary role is to engage in combat with enemies at medium range. Medic - Primary role is to revive and heal teammates Anti-Tank - Primary role is to undertake anti-tank warfare Engineer - Primary role is to repair or destroy vehicles Support - Primary role is to provide suppressive fire against enemies and resupply teammates Special Forces - Primary role is carry out stealth and sabotage missions Sniper - Primary role is to engage targets at long distances. Vehicles The various forces still use the trademark feature of the Battlefield series – the large stable of vehicles that any player can climb into and control. There are many different types of vehicles playable in Battlefield 2, all based on real-life vehicles used by the militaries of different countries. In contrast to Battlefield 1942, Battlefield 2 has only one purely water-based vehicle, the rigid-inflatable boat; however, the BTR-90, the MEC APC, can travel in water as well as the LAV-25 and the WZ 551, the USMC and PLA equivalents, respectively. The developers tried to design the game so that every vehicle would be weak to another type of vehicle, intending to create a situation similar to a game of rock-paper-scissors. For example, mobile anti-air was intended to effectively destroy helicopters, but are vulnerable against opposing tanks. Included within this relationship are stationary defenses such as light machine guns and anti-aircraft/TOW emplacements. The availability and number of certain vehicles are dependent on the map and its size as well as control points captured. Also, more vehicles become available to be used on the maps of expansion/booster packs. (see Maps). The USS Essex is the only naval ship featured in BF2, featuring two spawn points and aircraft spawn points, and is not drivable or destroyable, except for its Phalanx turrets. Squads Players are able to form squads of up to six soldiers in order to more effectively work as a team. Up to nine squads are permitted per team; each squad has a number (automatically assigned) and name (usually a phonetic alphabet letter) for identification. Members of a squad have the ability to communicate with one another via Battlefield 2s integrated voice over IP (VoIP) system. Squad leaders may assign their squad