The Guardian 4 sensor is a device that helps people with diabetes manage their glucose levels. It's part of the Continuous Glucose Monitoring (CGM) system and works by converting tiny amounts of glucose from under the skin into an electronic signal. This signal then provides information about glucose levels, helping people make informed decisions about their treatment.

The Guardian 4 sensor is designed to complement, not replace, the information obtained from standard blood glucose monitoring devices. It's a single-use device that can be used for up to seven days and doesn't require a prescription. Users can refer to the system user guide to make treatment decisions based on the sensor's readings.