In order to drop even more weight, the Hyperlite Mountain Gear packs have done away with frames in some models. Certain packs still utilize a rather neat and creative style of framing that doesn’t require adding a huge load.
These packs use frame stays. Frame stays are two thin aluminum rods that slide into the back of the pack and are sewn neatly into the hip belt to transfer weight from your shoulders down onto your legs. The stays are easily adjusted to fit your back, and work well to keep the pack’s shape while standing alone.
The stays aren’t nearly as durable or resilient as other pack frames, but work well for how lightweight they are. Aluminum is incredibly tough and barely weighs an ounce. Some people may find they want more rigidity, but everything is up to you.