Corrugated plastic now has vertical flutes so sign can be used with step stakes.
Gempler’s® WPS warning sign is now available with vertical fluting, so it will slide onto the top of a step stake (sold seperately as Item No. 159971). Just like the original, it is wind- and weather-resistant, reusable, EPA-accepted, and constructed of heavy, 4-mil corrugated-plastic. Measures measures 16"x14". USA made.
2013 Master Catalog: Page 124