Happy Retirement 2023 Yard Sign, Coroplast Black Gold Happy Retirement Lawn Decorations, Retirement Yard Sign with Metal H-Stake. Economical and durable, our Coroplast Yard Signs are a staple of outdoor advertising. This Officially Retire Yard Sign Decorations full color direct printed graphics are vertically fluted for use with an H-Stake. Coroplast is typically used for yard, parking, real estate, and election signs. They are waterproof.