Waterproof & Sweatproof: Kuruyo libre 3 sensor covers are waterproof and sweatproof,so you don’t have to worry about it peeling off while swimming or exercising. No glue in the center: This Libre 3 & 3 plus sensor covers with no hole & no glue on the center design, which make s it easy for you to replace the patch easier, and will not affect your sensor use.