Get the Osprey Uni-Sex 38L Backpack here: https://amzn.to/3cPxhNQ
If there is one gear item to purchase first, it would be an overnight backpack. Why? Because it is long lasting but it will hold everything you need for your adventure whether it is for a hike, airplane carry on, or for backpacking a country.
I currently own the Osprey Uni-sex 38L Backpack. My favourite feature are the many compartments/dividers to store your phone, sleeping bag, first-aid kits, etc., making it more accessible during and after the hike. Other features include:
Airscape backpanel with adjustable harness
Hydration bladder compartment
Side zipper access to main compartments
Trekking pole holders
2-side big hip pockets
Sturdy tightening straps and many carabiner options
Big mesh front pocket and mesh side pockets
Integrated removable rain cover included
Preference:
YOU can choose how many LITRES you need (depending how much you want to carry)
I chose a 38L bag as I wanted to eventually buy lightweight gear and to only bring the essentials. That being said, I find this one to be perfect size !
Backpack Fact: I have completed a 5-day trip with this pack many times.
Suggestion for a multi-day trip : One hiking partner carries the FOOD while you carry the TENT.
Get the Osprey 38L Backpack here: https://amzn.to/3cPxhNQ in Kestrel Picholine Green (Small-Medium 38L)
