You can combine the two backpacks together for more storage or use the small and large one separately. It’s 2 backpacks for the price of one. The small backpack has a laptop sleeve and lots of space organizational pockets. I am not a hiker and purchased this for one singular trip to travel to multiple countries in Europe and it was never used again. I purchased this around 2018 and there is no size tag. From experience it can fit anyone from a size XS woman to a size M male of average heights. The smaller bag in the front is an average backpack size and can fit at least a 15" laptop screen. Let me know if you have more questions.