This is a good intermediate pack if you don't want a ruck.
It has molle attachments and will allow you to attach a field knife or other molle attachments. Comes in various colors such as multicam, coyote tan, sage, and etc.
It is made with mil-spec 1,000 cordura which is very durable for heavy use, will let you put in a 100 oz. hydration pack, I believe it has bottom cords for strapping up a tent. I got a smaller assault pack and after time I realize I still want more room. Hence why I recommend this. If you need anything bigger, you need a ruck bag. It can also be adjusted if you also want a tac-vest or plate carrier.
Here is what they look like:
-A /k/ommando & Ron Pauler.