The Nook Tablet's design element: A faux carabiner clip

The $249 Nook Tablet from Barnes & Noble costs $50 more than the Amazon Kindle Fire and has about double the storage and memory. But there's also something else about the Nook that caught the eye of teardown experts at iFixit : A metal loop at the lower left corner of the metal cover.

The metal loop at the bottom left of the Nook Tablet, looks like a carabiner clip, the metal clip frequently found on backpacks.

It is the Nook's "carabiner clip," iFixit said, noting that this design feature is "not [an official] spec, but come on ... it's a carabiner clip."

The tablet's metallic loop, similar to what's seen on backpacks everywhere, draws its popularity from rugged metal clips used in rock climbing. Barnes & Noble didn't draw attention to the feature when the Nook Tablet was released last week.

The Nook Tablet's microSD slot, for added storage capacity, is located under a magnetic cover next to the carabiner clip. That location, iFixit quipped, "could make changing your SD card while rock climbing a bit difficult if you're using the Nook as a tie point."

The iFixit commentary, while tongue-in-cheek, does raise some questions about the open loop design. When asked whether Barnes & Noble expects customers to attach keys or other gadgets to the loop, one Barnes & Noble store representative said no. The loop is intended as an indicator of the SD card slot location, and will protect the magnetic cover inside the loop when opened, the rep said.

IFixit made a number of other insights about the Nook in its teardown, noting that while it has 16 GB of internal storage, double that of the Kindle Fire, only 12 GB of that 16GB total is usable for content such as books and movies, and just 1 GB of that can come from outside the B&N app store. "If you want to put your own content on your Nook, you'll have to use a microSD card" of up to 32GB, iFixit said.

The teardown also found the Nook Tablet had a 3.7 volt, 4000 mAh battery, advertised as providing 11.5 hours of reading time, more than the Kindle Fire's eight hours.

Both the Nook Tablet and Kindle Fire have Texas Instruments OMAP 4 1 GHz dual-core processors . Both also have 7-in. displays made by LG with resolution of 1024 x 600 pixels.

IFixit said it found a major chip difference between the Nook Tablet and the Kindle Fire: The Nook has a capacitive touch panel controller chip from Focal Tech, while the Kindle has no such feature.

The iFixit pros also took apart the Kindle Fire last week. While iFixit focused on hardware in both new tablets, many reviewers and analysts have noted Amazon's well-known content ecosystem for buying games, books, apps and movies as its main advantage over the Nook Tablet.

Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen or subscribe to Matt's RSS feed . His e-mail address is mhamblen@computerworld.com .

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