Birkenstock Arizona Unisex

I love me some Birkenstocks. I'm 7 months pregnant and the only shoes that are comfortable and fit my poor feet are my other pair of Birkenstocks (Gizeh; ~2 yrs old now), so I decided to invest in another pair. This is my first time trying the 'Birko-Flor' material (I usually like real leather), but I've been pretty happy with it. We'll see if it holds up as well as real leather. My normal shoe size is a 7.5; my Birkenstock size is a 37.The shoe was not delivered in a genuine Birkenstock shoe box (just a plain cardboard box), which immediately raised concerns about authenticity/counterfeiting. However, I inspected everything I could about the shoe and compared them to my other pair and I believe they are genuine. The are absolutely comfortable so if they are fake, my feet aren't complaining.