Go full pro with waterproof Signs! Our rigid Coroplast, PVC, Foam core and Signs can be used to promote promotional products, advertise real estate events and much more. They make it super easy to boost visibility and give businesses a polished and professional look. The standard for temporary signage, coroplast yard signs, and step stakes help celebrate everything from Grand Openings to Birthdays. Coroplast yard signs are an economic solution that can be single or double sided. Usually 18x24.