This is P2B preferred swaddle. Yes that is one hand out.
I find (most) baby’s like the freedom of one hand out…. remember they had 2 free hands in utero that they could suck and flap around. Having a hand out early allows them some familiarity, a hand to suck on if need be to self sooth and easier transition to 2 hands out when rolling.
2 free arms isn’t recommended until later because of their startle reflex (which they don’t outgrow until 3 or so months). I love a good stretchy material for the swaddle. Swaddle firmly, ensuring their legs/hips are left free.
As a midwife for … lets just say well over 20 years (not keen to show my age)… I can swaddle firmly. Some parents struggle with this and that’s where the sleeping bags become an easier option.
I do however, even with a sleeping bag encourage 1 hand out by no later than 4 weeks. Which is why the ergococoon is my sleeping bag of choice.
Remember all baby’s are DIFFERENT. This swaddle may not work for your baby and that’s ok. Life would be boring if we were all the same!