Even though it belongs to the regular Army, the ARW is a unit apart. This unique unit, due as much to its missions in Ireland as to the individuals that comprise it, is considered capable of carrying out the most difficult of tasks. Moreover the Australian Commander in Chief of INTERFET in East Timor had no hesitation in saying that he had never known any Special Forces unit as modest and discreet as the Army Ranger Wing.

Officially, the ARW is called "Sciathan Fianóglach an Airm" which can be translated as Army Ranger Wing. In any case it is a modern translation since Fianóglach is a Gaelic word borrowed from the ancient Fianna, the legendary Irish warriors. These traditions of ancient Ireland are as evident in Ireland's armed forces (Óglaigh na h-Éireann) as they are among rangers, who carry the Fianóglach flash on their shoulders.

There is no age limit for prospective rangers who must undergo a Ranger selection course which takes place annually. According to the Commander age does not count, only physical condition makes the difference. The oldest is 44 and average age is 31. In Timor they mixed the old with the new in a way that made the unit very cohesive. Every year between 40 and 80 candidates arrive and after 4 weeks of a selection course less than 15% remain. These 4 weeks are organised into 2 distinct phases. In phase 1 everybody starts at zero - the instructors showing the basic requirements to become a Ranger, that is to say a special forces soldier. Candidates must also pass a number of physical tests, water confidence training, assault  courses training, individual navigation tests as well as an 8 Km combat run test. On average they will get 4/5 hours sleep per night and are put under constant pressure from instructors and the course alike. If a candidate fails more than 3 out of the 9 basic tests he is returned to his home unit. A selection course may only  be attempted 3 times by any candidate. The 3rd and 4th weeks consist of long range reconnaissance patrolling which incorporates training as well as testing of personnel. Candidates are taught special forces tactics, reconnaissance  and surveillance, intelligence gathering and the achievements such as the search for enemy forces teams and the organisation of ambushes. The course culminates in a 45 Km march which must be completed in a set time. All candidates who successfully complete the Ranger course are presented with the Fianóglach shoulder flash. When it comes to selection the Officers and NCO's meet to assess the candidates. The best are retained according to the number of places available. On average, Officers spend between 3 and 4 years in the unit.

It is important to emphasise that during this selection course the tests are the same for Officers, NCO's and men. During these weeks there is no rank - only the qualities of the candidates count. For those selected there is still a long way to go. For 6 months they must undergo a Basic Skills Course, this time in an instructional detachment where they continue to wear the black beret.  The candidates will receive instruction on all weapons available to the ranger, and all the other skills need to allow them to integrate into the unit. It is only after this course is completed that successful candidates get to wear the coveted green beret of the Army Ranger Wing.