These wide angle lenses enable you to see an enlarged view not available through your inside rear view mirror. They dramatically increase visibility and confidence when parallel parking or backing up. The lenses are flexible and easy to attach. They easily apply to the inside of your rear window to eliminate rear view blind spots and increase viewing. Their thin, polyvinyl construction clings to your window without using glue adhesive and they will not turn yellow or damage your glass. The lenses become crystal-clear 24 hours after application, will stay on until peeled off, and can be cleaned using mild detergent and water.