Organization
The placement of this pack’s features are intuitive and well thought out. For example, you can reach your water bottle without having to swing the pack around to your front. Once the pack is in the front position there is a convenient work surface for changing flies: A fly patch sits on the right and keeps to-go flies at the ready, and the tippet storage is within easy reach. There are three zippered pockets and eight separated sections. All interior pockets use light-colored nylon that makes dropped flies easy to spot. The secondary compartment uses an innovative way of attaching zingers, keeping these attachments from cluttering up the pack’s exterior: Pin the retractor to the inside, then feed the tool through a slit that lets you reach it from the outside. The chest strap even features a nifty way to hold a hemostat (a magnetic closure lets you yank it out of the pocket with one hand). But as with most slings, there’s no handy place to hang a net: Shoving it into your wading belt is the best option. 

Comfort
The foam shoulder strap distributes the pack weight well (rarely more than 6 pounds, given the pack’s modest carrying capacity) and is comfortable for hours-long fishing sessions. 

Adjustability
Both the shoulder and side straps are adjustable, but the Orvis Safe Passage Sling Pack fits medium and large builds best.

Ventilation
The molded foam backpanel isn’t the breeziest system, but the pack’s small footprint limits the clamminess to a very small zone. We found the ventilation to be perfectly adequate for hot-weather fishing.

Water-resistance
The bottom of the pack is made of waterproof fabric, so a quick dip won’t require hours of gear-drying time later. But there’s no waterproof pocket for a phone (a Velcro strip mates with Orvis’s $12 waterproof pocket, which is sold separately).

Capacity
At 10.5 L, this is not the bring-everything (including the “kitchen sink”) pack. But it is big enough for everything that most anglers need for a lunch-hour session on the river: A couple fly boxes, a granola bar, and sunglasses. It’ll hold a packable, ultralight rain shell, but bulky models strain the capacity.