Papakura, New Zealand—The New Zealand Defence Force (NZDF) has released a rare glimpse of the secretive New Zealand Special Air Service (NZSAS).

The video reveals the unit’s high-tech training facility and offers a taste of the operators’ daily routines and training regimens.

Additionally, the NZDF sanctioned an interview with the New Zealand Herald, which produced a second video on the unit.

The NZSAS is famous for its secrecy and professionalism. You will not find any books written by former operators. You will not find any movies depicting the unit’s missions. The only thing that you will find, however, is an official documentary that describes the selection and assessment process. The documentary was sanctioned by the NZDF and the unit in an attempt to attract more applicants to NZSAS’ ranks. Following the U.S. Special Forces 18 X-ray example, the NZDF even permitted civilians to try their luck at selection.

Few soldiers and civilians, however, could amass the grit, determination, or operational intellect to become SAS operators. In four years (2013-2017), only 31 out of 243 applicants managed to get through—a 12.7 percent success rate for all the courses within the four years.

“So, for example, one of the most commonly reported motivations to join the unit is something along the lines of being useful,” said Captain Alia Bojilova, the former unit psychologist.

Selection is gruelling 10-day process. Food is limited, sleep almost non-existent. It begins with two days of pre-selection. Candidates must complete the NZDF fitness test (push-ups, sit-ups, pull-ups, and a run) but with SAS standards. And then the nightmare begins. And it won’t cease for the next eight days. Exercises range from individual land navigation to team activities. One of the latter called “von Tempksy,” has candidates march for 24 hours in a straight line carrying their 80-pound rucks and 20 liter jerrycans; that means through whatever hellish land feature the instructors have planned (sand dunes, thick vegetation, bogs, you name it). Selection culminates with a 38-mile ruck march carrying around 100 pounds of gear.

“And pretty much, it’s head down, bum up and keep moving. You haven’t had a lot of sleep, you haven’t had a lot of food to keep your body going. And you’ve really been working your body hard for about the last seven days or so. I’ve seen guys staggering and falling over and basically pretty much crawling over that last five, ten metres,” said John ‘Horse’ McLeod, an 18-year veteran of the unit.

Females are allowed to serve in the unit in support roles. NZSAS accepts candidates from all branches of the NZDF. Army candidates, however, do have an advantage, especially if they have served in the infantry, as they would be familiar with many of the selection tasks—for example, the relentless rucking.