This medium sized bag comes with a lot of hardware, which makes it look super stylish and professional:
The strap ends are connected to gate rings, which are then hooked into grommets on either top corner of the bag (gate rings are rings that you can snap open). The flap closes with a magnetic snap.
I decided to keep the strap simple, it is approx. 29 inches long. I made it thinner than you might expect it to be (it is about 0.75") which makes a nice contrast to the big gate rings.