Red Reflector Warning Signs- 18x18 Red Reflector Warning Sign - 18x18 are constructed of rust-free, .050 gauge, powder-coated aluminum Red Reflector Warning Sign - 18x18 are using Nine Diamond Grade (DG3) reflectors Red Reflector Warning Sign - 18x18 is rated by 3M for at least 7 years no-fade service Red Reflector Warning Signs - 18x18 come with holes drilled at top and bottom center for easy mounting