LARGEST POSSIBLE CARRY-ON RUCKSACK Traveling hands-free is freedom and nobody brings a roll bag on an adventure. Never check a bag and never drag anything behind you ever again with GR3A(R). The 45L GR3 is the largest possible carry-on rucksack, sized to fit in the overhead bin of all major airlines. The 35L GR3 maximizes packing space in a compact form factor, sized to fit in all overhead bins. It&';s big, tough, and overbuilt with the best Specs + Materials on the market. Proudly backed by our Scars Lifetime Guarantee.