How do you know if a travel gadget is worth giving?

It ought to make at least one tiny aspect of a trip less aggravating, or save time, or money, or some combination. The item should be easy to use, easy to pack, and should easily pay for itself.

Above all, the gizmo must be so practical or cool that it’ll provoke looks of undisguised admiration from fellow travelers, several of whom will ask where they can get one.

Many travel-related products out there don’t fit any of these criteria. Here are five that do.

Gadget #1: Travelon Portable Luggage Scale, $9.99

The night before a family vacation flight last winter I visited several neighborhood dry cleaners, asking if I could weigh my bulging suitcase on their laundry scales.

The first dry cleaner refused. He was afraid I’d break his scale. The second dry cleaner said yes, and I broke his scale. Temporarily – it flat lined for ten horrible seconds until the red needle snapped back to life. I got out of there before verifying that my bag weighed less than my airline’s 50 lb weight limit. Then, as now, most carriers will charge overweight bag fees of $50 to $150 for bags 51-70 lbs, potentially as much as $175 if the bag exceeds 70 lbs. At a third dry cleaner my bag weighed in at 43 lbs, which I double-checked at a fifth location before lumbering home.

I yelled to my wife, “You know what we need? One of those things,” generically known as a portable luggage scale. Digital versions exist, but given the unpredictability a dying (or dead) battery can lend to a digital reading, I’ve become a fan of Travelon’s old-school analog model. Weighing in at $10 or less at several retailers, the scale will pay for itself many times over before you go and before you fly home.

At 4 1/4" x 4 1/4" x 3" when unextended, the device from top to bottom is a handle attached to a 75 pound capacity scale, attached to a spool, attached to a formidable-looking metal hook. Slip your bag’s handle onto the hook, hold the handle up and out, and get a reading. That’s it. The spool casing also contains a tape measure so you can see if your bag has ballooned into the 62-80” range and qualified for a $50-$100 oversized bag fee.

Gadget #2: ReTrak Retractable Stereo Earbuds, $9.99

Try to ball park how much time you’ve spent, life to date, untangling your MP3 player’s earphone wires. Do you have a guess? That’s a lot of time you’re never getting back, right?

Several retailers sell buds whose wiring retracts along a tiny enclosed spool, and Emerge Technologies ReTrak Stereo Earbuds at $9.99 a pop could be particularly thoughtful stocking stuffers for your brood or anyone else’s traveling with MP3s, portable DVD players, and hand-held gaming devices in need of silencing. You’ll have 3.5 feet of cord to play out and the plug ought to be compatible with most of your existing portable devices. There’s a tiny clip on the spool if you need it, but the real treat is whipping the buds out of a pocket and plugging and playing without delay.

Gadget #3: Tugo Suitcase Cup Holder, $9.95

Flight attendants see plenty of travel gadgets come and go, and one gizmo that’s been getting good word of mouth among them and other frequent travelers is the Tugo Traveling Drink Holder, which the manufacturer describes as “a pliable cup holder that securely nestles a drink between the upright pair of handles on your rolling luggage.”

If you’ve dealt with detachable cup holders you know they don’t often detach easily once installed, and the Tugo gets high marks both for its simple tie-between-the-handles set-up and easy stowage. Preventing a drink from spilling is, of course, central to a cup holder’s job description, and by all accounts, it does its job: once you begin dragging your wheelie bag behind you, the holder pivots your cup so it remains perpendicular to the ground. Once you return your bag to its upright position, the holder pivots your cup back to its default position in line with your bag’s handles.

This is a thoughtful road warrior gift that’ll likely be co-opted by over-caffeinated, wheelie bag-pulling high-school kids. But the real gift isn’t the cup holder itself, but what it enables: a free hand.

Gadget #4: Vivitar Underwater Digital Recorder, $99.99

The Flip digital camcorder has given legions of travelers the means to look cool while they seek out hilarious moments to record. But if you really want to help a friend get his 007 on, give him the means to shoot intelligent life down under…water. Vivitar’s DVR 850W is an 8.1 megapixel digital video camera available from online and street-store retailers for about $100, reasonable given that comparable products in this category sell for two- and three-times the price.

The DVR 850W also distinguishes itself by how low it goes: Sanyo’s take on this camera remains waterproof to depths of up to five feet, and a Hammacher Schlemmer model handles 10 feet. The Vivitar goes 16 feet deep, at which point you might ask yourself how far down you really need to shoot. But if you have a snorkeler or diver in your midst who deserves something a little special, the 850W may be his thing. Among the extras is software that enables straightforward uploads to YouTube, thank goodness, as well as USB and AV cables. And, most critically, a wrist strap.

Gadget #5: iGo Charge Anywhere Battery Pack

A family vacation is never truly underway until someone utters the words “Did you pack my charger?” For some reason that question is directed exclusively at me and if people on your gift list are in the same boat, they ought to like the iGo Charge Anywhere, a battery pack implanted with a fiendishly clever feature: a foldable wall-blade plug.

Plug it in to a standard AC outlet and the battery will charge itself and a couple devices via cords connected to the battery’s two USB ports. Various phones, cameras, MP3 players, and gaming devices are supported. Unplug the juiced battery and carry it with you to give your other gadgets a power boost – one at a time – throughout the day. Back at your hotel, plug the battery back into the wall to recharge it and other devices.

There are a few catches: You’ll need to purchase an adapter tip for each device you want to charge, though iGo throws in the first tip for free. Power tips for my household’s two different-model phones and MP3 player were priced at $7.49 apiece; our camera and gaming device were unsupported, which was unfortunate given that iGo claims to have tips compatible with more than 3,000 devices. Also, a single USB cable is provided and you’ll need to buy a second one to charge two devices at once.

Despite the add-ons and compatibility issues, the Charge Anywhere’s ability to recharge itself and other gadgets, plugged and unplugged, makes it a good pick for families, business travelers, or anyone who’d like to purposely forget to pack at least some of their device chargers.

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