From Men’s Journal:

“GORUCK builds packs that are stout enough to take whatever you can throw at them. The 34-liter GR2 is the Goldilocks of the company’s line-up, just large enough to fit a weekend’s worth of suits and shoes, tools and coveralls, but small enough to comply with carry-on regulations. And while that’s true of just about every other pack of this size, the GR2 was designed as a tool, not as a fashion accessory.” 

Read more here.