TUMI CFX Southington Carbon Fiber Backpack It's not bulletproof, but TUMI's Southington Backpack does have a carbon fiber construction and ID Lock features strong enough to protect your tech and gear from the dangers of the daily commute.The TUMI CFX collection is set off by its American-made carbon fiber CX6. In addition to its carbon fiber shell and leather trim, the Southington bag is built with TUMI's ID Lock, a layer of protection for the personal data encoded on most of your IDs