The Peak Design Travel 45L Backpack functions as a day bag carry-on or checked bag for all of your travel needs. The backpacks default 35L configuration meets the maximum international carry-on standards so you can confidently fly. Or if you need a little extra room dual expansion zips offer an extra 10L and the durable face fabric and ultra-light foam padding keep your gear protected so you can check the bag with peace of mind. Conversely compression snaps reduce the bag to 30L when you're out on a day trip while tons of internal and external pockets help you keep all of your gear organized throughout the duration of your travels wherever they may be.