In an embodiment, an apparatus includes a module assembly and a main assembly. The module assembly includes a module assembly housing, a first faceplate and an analysis unit attached to the first faceplate. The main assembly includes a main assembly housing, a second faceplate and an engine unit rigidly attached to the second faceplate. The engine unit generates a light that passes to the analysis unit via a first lens assembly and a second lens assembly. The first lens assembly is attached to the first faceplate and the second lens assembly is attached to the second faceplate. The module assembly when attached to the main assembly causes the first and second faceplates to act as a single mechanical unit that moves independent of movement of the module assembly housing and/or the main assembly housing.