For years Just Mobile has been making things out of aluminum, nice and helpful things too. Its aluminum-made rechargeable backup battery packs were and continue to be one of the nicest looking on the market. To grow and improve its line of electricity harnessing banks, Just Mobile's most recent release includes the Gum++ (or Gum Plus Plus), a 6000mAh external backup battery follow-up to the aluminum-made Gum Plus that boasts an ultra-portable form factor that features a high-powered USB output port capable of filling up smartphones, tablets and just about any inanimate object that's got a USB port on it with extended hours of usage.

Redesigned with a hard-wearing ABS plastic shell, the Gum++ is supposedly more durable than its aluminum predecessor and can charge your smartphone up to three times over. As always, we conducted our own testing using multiple devices to find out if any of these claims really stick. Our full review awaits!

What's more versatile than a smartphone-specific battery case and a lot more powerful at the same time? Behold, the mighty power of the rechargeable external backup battery. These packs of energy juice for gadgets come in many shapes and capacities, but we haven't seen a lot of accessories that are as cute and well designed as Just Mobile's Gum series of batteries. A portable backup battery is one of the more essential pieces of kit anyone with a handheld device should carry or at least have around just in case the unthinkable happens. Just Mobile's Gum++ feeds the needs of power users as well as those who have fallen victim to poor smartphone battery life with honest energy delivered as quickly as possible. Its highlight is its compact form factor to internal battery capacity ratio which needless to say...is pretty impressive on top of its svelte, albeit seemingly tough styling and sharp LED battery life status gauge.

Retailing for $90, the Gum++ comes in white, silver and black colors which retain the contrasting black middle layer that every Gum battery has, and I wouldn't have it any other way. This white colored Gum++ we're reviewing is a really attractive little pack with that black layer sandwiched in-between forming what looks like an inside-out ice cream sandwich type of tone that's pleasant to have around; that is if you care about what your battery looks like which you should because ultimately good design leads to better user experience and happiness all around.

Straight out of the box the Gum++ comes with one short black micro-USB to USB cable you'd use to charge the Gum++, and some information on how to get started. Because the Gum++ is marketing as an external backup battery that can charge any USB device, you'll have to use your own USB cable that you normally use to charge your device with.

Alternatively, you could also use the supplied micro-USB to USB cable with the Gum++ to charge your device like the Galaxy S4 by swapping ends. The short cable makes it convenient to carry and use if you just plan on leaving your device off to the side to charge. Pro tip: You can purchase Apple's tiny Lightning to Micro USB Adapter, that way you'll be able to use the Gum++'s short charging cable with your Apple devices instead of using a separate Lightning connector to USB cable which you'll be able to leave back home or at the office.

On one side the Gum++ features a single USB charging output where you'll plug in your device's USB charging cable to begin charging. All you have to do is press the one and only button found on the entire unit which happens to be located right at the top near the battery status LEDs which will constantly remain lit displaying the remaining battery life left in the Gum++ until you turn off and stop the charging process. These piercing green LEDs are tough to capture on camera, but they're easy to read in person, laser-sharp in quality and shine bright just like the green LEDs Apple uses on its MacBook Pros. It might not be the most important aspect when talking about a backup battery, but Just Mobile's LED battery status gauge has always impressed and satisfied me the most. I guess you could say it adds an extra bar to the user experience.

On the opposite side, a speedy 2.5Amp micro-USB input is used only to charge the Gum++'s internal rechargeable battery. Whilst charging up, the green battery LED indicator gauge will blink until it fill up completely letting you know when it has finished charging.

Size matters when you're traveling and trying to keep your gear as light as possible. This is where the Gum++ really comes into play. Its ultra-compact form factor means you can easily slip it into your pocket. I'm not talking about your gear bag's pocket, but your actually pants pocket. If convenience is key, this is the way to carry 6000mAh of backup electricity on your person in a comfortable way. The rounded, sleek shell of the Gum++ fits into tight spaces while only making it look like you've got roughly two very short iPhones stacked against each other in your pocket. It's smaller and slimmer than a typical Altoids tin, that's how pocketable it is. Although the Gum++ isn't anywhere near as awesome as Just Mobile's 11,200mAh-packing, dual-USB equipped - aluminum covered Gum Max Duo, it serves a purpose as a midrange battery option that's small enough to be carried on your person unlike the gear bag requirement needed when using the Gum Max Duo on the go.

What makes the new Gum++ a good portable backup battery is the fact that it can charge your device quicker than others saving you time and money. Well, maybe the money part doesn't always apply but when it does, you'd surely thank the speedy USB charging port on the Gum++. Because with its impressive 2.5A USB output, charging up a common device like the iPhone 5 takes no longer than it does when you plug it in using an Apple USB Power Adapter. It's fast, faster than a lot of competing batteries out there which don't have such high-powered USB power output necessary to pump energy into other devices. Conversely, the Gum++ also features a 2.5A micro-USB input that enables it to quickly recharge its internal battery. However, filling up a 6000mAh tank takes quite a while and still, it's a faster recharge time compared to other offerings.

Talking pure performance, in our testing the Gum++ performed more adequately compared to its advertised charging capabilities. Starting with one of the bigger smartphones we used, the Gum++ was capable of refueling the Samsung Galaxy S4 one and a half times up from a totally depleted battery. As for the iPhone 5 and its smaller built-in battery, the Gum++ had enough power to nearly charge it up three times. To be more specific our testing yielded two full charges plus an additional 70% charge from a completely depleted state. That's more than enough to keep you up and running throughout an entire day of heavy use, and then some. To protect both your device and its internal battery from overheating or overcharging, the Gum++ will automatically shut off once it has fully charged your device.

Design wise, Just Mobile went to plastic to construct the Gum++ while keeping the original rounded-edge shape and in doing so, it hasn't dropped the price. It's not to say that the Gum++ is cheaply made because it isn't. Quite the opposite actually. The build quality is really good giving the Gum++ a very solid and tightly packed weight and feel. The smooth rounded aluminum enclosure is replaced with what Just Mobile calls a hard-wearing ABS plastic shell which has a glossy smooth finish to it with ridges made to look like a tough hardshell luggage or briefcase. Out of the countless backup batteries I've seen, this is probably the most favorable compact design of mine.

As for that hard-wearing ABS shell, some of the white colored finish on some of the ridges looks worn off straight out of the box upon close inspection. The good thing is that these ridges keep most of the flat surface away from coming in contact with the surface which means that there's less chance wear on the plastic shell won't be as significant over time.

I would have liked some type of rubbery feet positioned at the bottom of the Gum++ just to give it traction on smooth surfaces, alas Just Mobile always kept its battery packs rather slippery all around for reasons unknown. And even with that being said, other than the price, I don't have anything bad to say about the Gum++ because it does what it you expect it to do excellently.

With a $90 price tag, the Gum++ is one expensive proposition as far as backup batteries are concerned. You could easily find a cheaper alternative with a lot more capacity often made by lesser known brands, notably the $45 8400mAh Photive Power Bank, but we question their reliability and quality. Just Mobile's Gum Max has been my go-to external battery charger ever since I reviewed in back in 2011. And it's still going strong and has been extremely reliable all this time which ratifies the quality you get with a Just Mobile battery pack.

One latest exception is SwitchEasy's Tanks, an equal rival to the Gum++ which also features a 6000mAh internal battery capacity for $70. But there is a small difference in power output when comparing the two battery packs. The Gum++ is considered to be superior due to its faster, more powerful 2.5A USB charging outlet whereas the Tanks is rated at 2.1A. There's also a considerable difference in styling that might deter you from picking on or the other.

And there you have it. Should you buy the Gum++? From a naming standpoint is does sound like it offers a lot, but in reality it's expensive for its internal battery capacity. But if you want a high quality, ultra-compact and pocketable backup battery pack that actually performs really well for its small stature, then by all means we do recommended it for its fast performance. Otherwise we suggest you look elsewhere preferably starting with SwitchEasy's comparable $70 Tanks.

Just-mobile.com