I Support Ukraine 2022 Yard Sign - Coroplast We Stand With Ukraine Sign, Support Ukraine, Ukrainian Flag Yard Sign with Metal H-Stake. Economical and durable, our Coroplast Yard Signs are a staple of outdoor advertising. These outdoor Support Ukraine Yard Sign 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.