We all carry a water bottle with us — and if we don't, we should — but unless your bag has a dedicated bottle pocket, odds are it just doesn't fit that well. But what if your bottle was designed like something your bag already holds, like a notebook? That's the idea behind the Memobottle. Available in three sizes — Letter, A4, and A5 — these bottles are designed to fit in your bag alongside your books, laptops, tablets, and other rectangle-y things, and hold between 750ml to 1.25L of water. Best of all, they help keep plastic bottles out of landfills, since their dishwasher-safe, BPA-free Tritan construction lets them be reused over and over again.