Timbuk2 Gist Backpack A riff on a Classic military rucksack, the gist is both tough and tender Dual side slip pockets for U-lock or umbrella Internal slip pocket fits up to a 15 inch MacBook Vista loop for attaching blinky bike lights Top lid mesh pocket Standard Version with Polyester main fabric and Violin YKK Zippers Premium Canvas version with PU Coated YKK Zippers and padded laptop sleeve