The Department of Homeland Security and US Customs and Border Protection San Diego, showed off eight wall prototypes near the Otay Mesa Port of Entry.
https://twitter.com/CBPSanDiego/status/918137332880019456
The prototypes, four made of concrete and four made of other materials, began construction last month and were expected to be completed within 30 days. The prototypes are expected to cost nearly $4 million. Six companies are taking part in the construction of their prototypes.