This medium Sling Bag has a gusset on the bottom that gives more room inside. 
Measuring 13” across and 7” tall the 2” bottom gusset allows the bag to expand with what you carry. It has a clam shell opening and two pockets inside.  It's 45-47” strap is for wearing like a Sling Bag across your chest or back and cinching smaller for the average person to wear around the waist.