A Continuous Glucose Monitor (CGM) is a medical device that tracks blood sugar levels in real-time. It consists of a small sensor placed under the skin, which measures glucose levels in the interstitial fluid. The data is sent to a display device, allowing users to see their glucose trends throughout the day and night. CGMs are particularly useful for individuals with diabetes, as they help manage blood sugar levels more effectively. By providing continuous data, users can make informed decisions about their diet, exercise, and insulin use, ultimately improving their overall health and reducing the risk of complications.