The incidence of non-melanoma skin cancers, due to increased ultraviolet (UV) exposure, has increased by 300% over the past 2 decades. The innovative UV sensor, Shade, is designed to help people manage their UV exposure by quantifying their UV exposure levels through a linked smartphone application. In order to validate the effectiveness of Shade, we propose conducting a study looking at the level of UV exposure and correlating it with the development of actinic keratosis (AK), a precancerous lesion of the skin. The risk of developing squamous cell carcinoma (SCC) in renal transplant patients is 65 times higher than healthy patients. We will evaluate the UV monitor's effectiveness in decreasing the number of AKs over a 12-month period. This randomized partially blinded study will recruit 120 kidney transplant recipients on immunosuppressive therapy with a recent history of an AK lesion and evaluate the incidence of new AKs over 12 months. We will perform a control versus study group analysis. Half of the subjects (study group) will be randomly assigned to use the sensor along with its smartphone application, while the other half (control group) will receive standard of care treatment involving counseling to avoid sun exposure. Subjects will have regular standard of care visits with the dermatologist who will follow the number of actinic keratosis via clinical exam and photography. The primary outcome will be a statistically significant reduction by at least 25% of the cumulative number of newly occurred AK lesions between the control and the study group over 12 months, counted at 3, 6, 9, and 12 months. Skin DNA damage will also be assessed using cyclobutane pyrimidine dimers (CPD) levels measured by ELISA in both sun exposed (cheek) and sun protected skin (buccal mucosa) in both the study and control groups. Secondary outcomes will look at clinical decreases by 25% in CPD levels after using the sensor.