WASHINGTON (Reuters) - The Trump administration has selected four construction companies to build concrete prototypes for a wall on the U.S. border with Mexico, U.S. Customs and Border Protection said on Thursday.

The four companies are Caddell Construction Co of Montgomery, Alabama; Fisher Sand & Gravel Co of Tempe, Arizona; Texas Sterling Construction Co of Houston; and W.G. Yates & Sons Construction Company of Philadelphia, Mississippi, the agency said.

The four contracts range in price from about $400,000 to about $500,000, CBP said. The prototypes will be 30 feet(9 meters) tall and about 30 feet wide and will be tested in San Diego, it said.