The Expandable Trek Backpack provides amazing storage space and versatility for the active, urban professional. This ergonomic backpack features multiple pockets and an expandability option that accommodates an additional 20%, this case support s all of your essential items for work and play. The front organizer pouch includes multiple pockets for your cell phone, pens, AC adaptor, etc. It also features a recessed mp3 player pocket that sits flushed on the backside of your backpack. Brenthaven's Expandable Trek BP is now 'zero impact' which means Brenthaven promises to invest in Green projects that offset any impact our products have on our environment.