I'm new to Balenciaga but I saw one the other day at Barneys and now I can't stop thinking about them. What is the difference between the City, First, and Work? Is it primarily a size difference? I was looking at a bag and the SA tried to tell me it was a small, medium, and large motorcycle bag. She didn't know what was a first, day, etc. I think it was a City, First and Work I was looking at but I can't tell from the reference area which it was. I'm looking for the middle sized one. I think it was a City of a First that I wanted.