LIHIT LAB Smart Fit Bag in Bag

 Japanese LIHIT LAB, maker of plenty of bags and pen cases, are experts in keeping your stuff in perfect order. This bag in water-repellent polyester has room for a notebook in A5 format and a serious amount of pens. The idea is that the bag should fit in your regular bag, but it's also possible to put on a shoulder strap (not included).