This was small enough to make life easy on a long trip, but large enough to carry essentials like iPhone, money, passport, tissue, tickets, etc.  It was easily concealed under my jacket.  What I liked least was wearing it around my waist.  I know that's the smartest way to wear it where pickpockets are aplenty, but I was so glad each evening to take it off.  It also functions nicely as a small cross-body bag.  If you need to bring a water bottle, this one won't work.