Ensures good back ventilation when youre hiking: the acs hike 38 pack is our classic hiking pack for day hikes and multi-day trips. It excels in carry comfort because it comes with our acs suspension system. Its key attribute is its excellent ventilation, making it a good choice when youre constantly on the move. A sturdy mesh back creates a gap between the pack and the back and lets the air flow freely.The classic compartment configuration, with main, base and lid compartments, is a tried and tested design. The base compartment is accessed separately from the outside. Small items can be stashed in the front pocket, lid compartment and zipped pocket on the waist belt, as well as the Elasticated pouches on the outside.