Insulin pen parts

• Large outer needle cap
• Disposable needle with a small inner needle cap
• Cartridge filled with insulin
• Dial or knob to adjust the dose
• Window or area to view the dose
• Button to give the shot

Some insulin pens are disposable and are thrown away when the insulin cartridge is empty. Other insulin pens are refilled by placing a new cartridge of insulin in the pen. Some insulin pens also have a pen cap over the outer needle cap.