Microsoft duo have very unique hardware in smartphone world.Duo is new approach of microsoft in foldables but is not logically foldable;it is basically 2 separate screens which is attached with excellent hinge.
Microsoft took a practical approach in foldable smartphone thing.It's duel screen amoled display is a key feature and very useful in real life.
the Microsoft Surface Duo had one of the most unique hardware we’ve seen in a while in years . This phone is shockingly thin, coming in at just 4.8 mm when unfolded, or about 9.6 mm when folded up. Compare that with any other phone, especially a foldable phone like the Samsung Galaxy fold or upcoming samsung z fold ; it’s clear Microsoft put a lot of work into making this thing as slim as possible.
When duo is unfolded it is shockingly wide. It’s clear that Microsoft wants you to use this phone with two hands, like a book.Since it is wider phone feels more like a tablet. At the end of the day, it still does most of the things a standard Android phone would do like call ,messaging ,gaming ,media stuff etc.