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Backpacks

Pack lid

Also called brain, top lid, floating lid

What is a pack lid?

The lid, or brain, is the padded flap that covers the top of a top-loading pack, usually carrying one or two zipped pockets. A floating lid is one attached by adjustable straps so it can rise as the pack is overfilled.

Pack lid at a glance

Also called
The brain
Floating lid
Rides on adjustable straps
Typical weight
3 to 8 oz if removable

What the lid is for

On a classic top-loading pack, the main compartment closes with a drawcord and then a padded flap folds over the top and buckles down. That flap is the lid, and hikers have called it the brain for long enough that both words show up in the same catalogue.

What belongs in it

It's the most reachable storage on the pack, which makes it the natural home for the things you want without taking the pack off: map, snacks, headlamp, first aid, permit. Most lids have a zipped pocket on top and a smaller mesh one underneath, and the underside pocket is where keys and documents live because it can't spill open when you unclip the lid.

Floating and removable lids

A floating lid rides on adjustable webbing rather than sewn in place, which lets it lift a few inches when you've stuffed the extension collar full. Some designs detach entirely and become a small hip pack for a summit push. Ultralight packs often skip the lid and use a roll-top closure instead, saving somewhere between 4 and 8 ounces.

What this means when you're choosing

  • Whether the lid floats, which is what makes an overfilled pack still close properly
  • An underside pocket, for things you don't want falling out
  • Whether it detaches, and whether the pack still closes cleanly when it does

The common mistake

Loading it heavy

The lid is the highest point on the pack, so weight there has the most leverage and the most effect on your balance. Keep it to light things you want often: map, snacks, headlamp, gloves. The heavy items belong low and against your back.

Common questions

What's the difference between a brain and a lid?

Nothing. They're two names for the same flap, and which one a brand uses is mostly a question of where it's from.

Is a roll-top better than a lid?

Lighter and more waterproof, with less quick-access storage. If you're happy keeping your snacks and map in hipbelt and side pockets, a roll-top is a straight saving; if you're not, you'll miss the lid within a day.

Where this comes up

Guides on Tom's Hiking where pack lid changes which product is right for you.

More in backpacks

Load lifters

Load lifters are the short straps running from the top of the shoulder harness back to the top of the pack frame. They pull the load in towards your body so it stops levering you backwards. They don't carry weight themselves.

Hipbelt

The hipbelt is the padded belt that wraps your pelvis and transfers pack weight onto your hips instead of your shoulders. On a loaded backpacking pack it should be carrying most of the weight, often quoted as 70 to 80 percent.

Framesheet

A framesheet is a sheet of stiff plastic in a pack's backpanel that spreads the load across your back and stops contents from poking through. It's lighter than a frame but gives you less vertical support.

Internal frame

An internal frame is the structure hidden inside a pack's backpanel, usually one or two aluminum stays or a perimeter hoop, that carries weight from the shoulders down to the hipbelt. It's what makes a pack load-bearing.

Suspended mesh backpanel

A suspended mesh backpanel stretches a taut mesh across a curved frame so the pack body sits away from your back with an air gap behind it. It's the coolest-running backpanel design and the one that holds the load furthest from your spine.

Extension collar

An extension collar is the fabric tube above a top-loading pack's main compartment, closed by a drawcord. Rolled down it does nothing; pulled up it adds capacity, typically 5 to 10 liters beyond the pack's quoted volume.

Panel loader

A panel loader opens with a zip that runs around the front of the pack, so the whole compartment folds open like a suitcase. The alternative is a top loader, which you access through an opening at the top.

Shove-it pocket

A shove-it pocket is the open-topped stretch panel across the front of a pack. It has no zip, so you can push a wet jacket or a map into it one-handed while walking, and pull it out just as fast.

Load rating

A load rating is the weight a pack maker says a pack carries well, usually given as a range in pounds. It describes the frame and hipbelt rather than the fabric, so exceeding it doesn't break the pack, it just moves the weight to your shoulders.

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