» What is it: A backpack with an inflatable bladder that fits in the small of the back, protecting the spine and the gear inside.

» The good: You can pack a lot of weight in this thing, making it heavy to lift. But once you hoist it onto your back, it doesn’t just feel OK, it feels comfortable. There’s something about having that air bag in the small of the back that feels a bit like a masseur applying pressure. I walked more than a mile with four bottles of wine, plus magazines and books. Not once did I feel the bottles against my back, because I was able to place them in two of the three large main compartments farthest from my back, and the pack has pads to protect the shoulder blades. The maker points out that the same cushioning that protects your back also protects the gear inside. Not only could the backpack swallow my regular laptop whole, I momentarily "lost" my netbook when it slipped to the bottom. I counted 15 compartments, including two for exterior water bottles. I abused this pack for two months with no signs of wear or dirt.

» The bad: Don’t remove the air bladder and expect to get it back in without deflating it. This can be remedied by accessing the filler tube through a portal in the casing. If using as a carry-on, I would deflate the bladder during flight, just to be sure it will fit into an overhead bin.

» Cost: $80 to $110

» Available from: airbac.com

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