Shade helps people manage their UV exposure_ it is a ultraviolet (UV) monitor with unprecidented accuracy connected to a mobile application. Although it is one of the clearest and most controllable causes of cancer, UV exposure can be difficult to estimate due to the importance of combining many rapidly changing factors including intensity, shade, and use of protective cloting and sunscreen. To validate Shade in a short study we enroll a highly susceptable population, transplant patients taking immunosupressive drugs. Kidney tranplant patients have 65 times higher risk for developing squamous cell carcinoma (SCC), and once diagnosed they have a far higher rate of developing metasteses and dying. SCC develops from precancerous, UV triggered actinic keratosis, a lesion with remarkably high prevalence in this population. This project will accomplish the following (1) recruit transplant patients undergoing regular skin checks, (2) provide them with Shade, (3) validate that Shade users see a decrease in symptoms and markers of UV exposure by dermatologist observation of actinic keratosis, and by a reduction in cyclobutane pyrimidine dimers a biomarker of UV exposure, and (4) observe changes in understanding of UV exposure through completion of a UV education survey at the beginning and end of the study.