Whereas most high-capacity power banks are sold in rectangular block chassis’, the Snooper Ventura is made of five cylindrical lithium-ion cells, held together with a bright orange silicon housing. This makes the PB60 not only flexible – you can roll it up to fit it into any space available in your rucksack – but easy to see in the dark and resistant to the elements.  While the Ventura PB60 doesn’t have any certifications as to its waterproofing, a silicon flap that conceals the USB and Micro-USB ports ensures it is both rainproof and shockproof. If you’re going camping or to a festival, the Snooper will also be safe from mud splatters and other less welcome spillages. Also see:  how to charge your smartphone or tablet faster.  The only part of this power bank that is exposed to the elements is its power button, which arguably could also have been concealed behind the silicon casing. Since the Ventura doesn’t support auto-on/-off, you’ll need to tap this once you’ve plugged in your device to begin charging.  Another plus point for the PB60 is its passthrough charging: you can charge your device at the same time as refilling the Ventura’s lithium cells. If you’re away from the mains, Snooper also sells a portable solar panel kit (£89.99), which will come in handy here.  Even without a mains refuelling source to hand, the Ventura PB60 offers 10400mAh of portable power for charging up your phone, tablet, camera or any other USB-charged device. It has a single USB output, restricting it to charging just one of these devices at a time; rated at 1.5A (7.5W), it provides reasonably speedy charging, too. You can find faster-charging portable chargers, but there are also many slower 1A (5W) devices on the market.  All power banks lose available capacity through heat generated and voltage conversion, so the 10400mAh on the packet won’t be what’s available to your phone or tablet. Snooper doesn’t specify the Ventura PB60’s efficiency, although in our experience most power banks average around 70 percent, with anything higher something to shout about in their marketing materials (Anker, for example, offers 90 percent efficiency with its Astro Mini).  So, you might find with a 100 percent charge the Snooper can deliver 7280mAh of power. How many times this will charge your device depends on its own battery capacity. As an example, an iPhone 6 has a 1810mAh battery, which the Ventura PB60 might fill four times. Android phones typically have larger-capacity batteries, so you might expect only three full charges.  If you are using the Ventura PB60 to charge an iPhone, note that only a (also bright orange and rubberised) Micro-USB cable is supplied in the box. You can use this with your iPhone charger to refill the power bank, but you’ll need to supply your own iPhone cable to transfer that power from portable charger to phone.  To show how much capacity remains one of the lithium cells carries four LEDs, which shine through the rubber casing.  Read next:  How to improve smartphone battery life. Follow Marie Brewis on Twitter. Marie is Editor in Chief of Tech Advisor and Macworld. A Journalism graduate from the London College of Printing, she’s worked in tech media for more than 17 years, managing our English language, French and Spanish consumer editorial teams and leading on content strategy through Foundry’s transition from print, to digital, to online - and beyond.