Dirty clothing is not an afterthought in the Aion 40L. Thule includes a removable TPU-lined rolltop bag, giving this model a practical distinction for trips where used active gear must come home beside clean clothing and electronics.
Separation you can take out
The removable bag can be useful when you want to unload one category without disturbing the rest. Its value depends on the contents you need to separate; a traveler with a simple, dry clothing load may gain less from it than someone returning from an active day.
The outer backpack provides dedicated technology storage, a bottle pocket and internal compression according to Thule. These features create a luggage-oriented setup rather than a bare fabric sack. Consider whether that organization replaces your existing pouches or merely adds to them.
Keep the 40L identity clear
Do not transfer the smaller Aion 28L's expansion figures to this model. The 40L documentation lists its own dimensions and features; a shared family name does not mean identical construction.
Thule offers an Aion Sling separately that can serve as a hip belt. If that function matters to you, include the accessory in the total configuration rather than assuming it is supplied with the backpack.
A sensible selection
This is worth comparing for a main travel load that benefits from gear separation. For daily outings with only a few essentials, its full luggage role may be more space than you want. Choose it because the interior solves a packing problem, then check the packed measurements against your transport requirements.
