Peak Design Travel Backpack 45L

I picked this Peak Design pack for travelers who want one bag that can flex between a daily carry and a full travel load, thanks to the 35 to 45 liter expansion. The rear and top access and the weatherproof shell are the details I weigh most when a bag has to work in airports and on city streets alike. Just check the expanded size against your airline's carry-on limits before you pack it out to 45 liters.