Box containing a continuous glucose monitor (CGM) sensor. The tiny disposable glucose sensor, which is about the thickness of a hair, is inserted under the skin and connected to a small transmitter patch that sticks to the skin's surface. It measures the levels of glucose in the interstitial fluid (the fluid around the cells), rather than in the blood. It records the glucose levels and trends, which are wirelessly transmitted and displayed on a reader held near the sensor or a smartphone app.