This depends on the type of case you have. ADW Diabetes has both hard and soft cases, as well as cases that store insulin, syringes, and diabetic pens. In addition, you can find organizers for your diabetes testing and treatment equipment.
Some cases are 6" x 2.5" x 1.25" and hold 2 vials of insulin, 2 syringes, and alcohol swabs; others are 5" x 6.5" x 2.5" and can hold a 1-week supply of diabetes products plus a frozen gel pack. Some cases have enough room for insulin, medical syringes, skin prep wipes, and two cooling packs.