All mecha are built out of individual modules, or what could be regarded as body parts. Each part contributes abilities and limitations, and not all parts can be installed on a particular type of mecha.
Body[]
The body is the core module of any mecha. It is usually the largest module, and it compulsorily contains the engine of the mecha, and optionally the gyroscope, if the mecha has one. The cockpit, sensors, targeting computer and ECM component are also frequently installed in the body. If the body of a mecha is wrecked, the mecha is completely destroyed; its other modules may be salvageable and its equipped components can be retrieved, but the mecha itself cannot be repaired. The body can contain up to two mounts.
Head[]
Many mecha have their sensors installed into their heads, because the sensors' effectiveness are increased by 3. Some battroids, like the Joust and Radcliff, also house their cockpits in their heads, which grants them one bonus point each to MV and TR, but makes them more vulnerable. Weapons mounted in heads also enjoy a 180° arc of fire instead of the default 90°.
Arm[]
Mecha usually come with two arms, or none. All battroids have two arms by definition, and some gerwalkers, like the Harpy, may also come with arms. Arms are the only modules that can contain hands, which are necessary for picking up salvage. Each arm can house up to one hand and one arm mount, allowing it to house two equipped weapons, and weapons equipped or installed in arms have a 180° arc of fire. Arms can also wield shields.
Leg[]
All battroids and zoanoids have legs by definition, and, again, some gerwalkers, like the Neko, may come with legs. One leg by itself is not very useful, but two or more legs allows a mecha to walk and run. Some zoanoids and arachnoids have more than two legs; the Scylla and Esher have four. Additional legs are an insurance against crashing, when a mecha is left with only one leg or none at all. Legs often house other propulsion systems as well, like wheels and thrusters. Each leg can contain one mount, which usually mounts a missile pack, as with the Savin.
Wing[]
Wings are not necessary for a mecha to be able to fly, nor do wings alone allow a mecha to lift off; the job is done with thrusters, hover jets and flight jets. All aerofighters, ornithoids and gerwalkers have wings by definition, usually two; other mecha are not normally manufactured with wings (although one may fit them with wings later). Mecha with wings usually house their propulsion systems in the wings, and may have one mount in the wing for weapons and additional propulsion. Wings may give a flight speed bonus depending on their size and the mecha type.
Turret[]
Turrets are most useful for their ability to spin around independent of their host mecha, giving weapons in turrets access to a full 360° arc of fire. However, turrets can only be installed in hoverfighters, groundhuggers, groundcars, and arachnoids, mecha types with other disadvantages.
Tail[]
Tails are often found on zoanoids, and sometimes on ornithoids as well, and are flexible modules that extend out from the back of a mecha. Weapons equipped via mounting point in a tail, like in a turret, enjoy a full 360° arc of fire. Weapons installed directly in the tail however only get a 180° Arc.
Storage[]
Damage to storage does not pass on to other components; that is, if a shot destroys a storage module, the overflow damage does not pass on to the mecha body. Pods is a short name for storage modules and has entered wide usage among mecha manufacturers. Storage modules are applied to numerous functions: aerofighters and gerwalkers, like the Shard and Harpy respectively, have propulsion pods; the Petrach houses missile launchers in assault pods, and the Phoenix uses a storage module as an armed "backpack".