Customs and Border Protection awarded contracts to four companies to build prototypes of concrete wall concepts that could one day be built along the U.S.-Mexico border.

Over 30 days, the companies – Caddell Construction Co. LLC, of Montgomery, Alabama; Fisher Sand and Gravel (Fisher Industries), of Dickinson, North Dakota; Texas Sterling Construction Co. Inc., of Houston, Texas; and W.G. Yates and Sons (Yates Construction), of Philadelphia, Mississippi – will build 30-foot-high, 30-foot-long sections near the border in San Diego, California. Once built, those prototypes will be judged based on aesthetics, how penetrable they are and the anti-climbing features being used, according to acting CBP Deputy Commissioner Ronald D. Vitiello, who announced the awards during an Aug. 31 press conference.

Compared to past border efforts, these awards are the result of a “more holistic view,” he said. “We thought through on these action plans all of the equipment that the agents’ need. This is a much safer environment.”

The awards ranged from just under $400,000 to just under $500,000. However, Vitiello warned against using those figures to extrapolate a larger cost for the entire border, as land purchases and geographic issues mean costs could vary greatly.

The prototype sections will be made largely out of concrete, though alternative materials might also be employed, Vitiello said. Additional awards for see-through, secondary wall sections closer to the immediate border will be made next week, he added.

Once built, the wall will “compliment the various other tools we employ to secure our border,” Vitiello said, mentioning sensors, cameras, lighting and others.

He also noted that these concepts will not be used along the entire 2,000-mile border. Rather, the final sections will be built “where impedance and denial makes a difference,” based on enforcement data and past immigration patterns.

The winners were among more than 180 companies to submit proposals based on two RFPs issued by CBP in March of this year.

As the prototype construction gets underway, CBP officials plan to work with the companies and others in industry to identify the best solutions and outline a plan to build out the wall along sections of the U.S.’s southern border.

“Prototyping is an industry-tested approach to identify the best solution when considering a new product or methodology,” CBP said in a release announcing the RFPs in March. “Through the construction of prototypes, CBP will partner with industry to identify additional means and methods to construct a border wall before making a more substantial investment in construction.”

Vitiello said this stepped approach is meant to ensure CBP is “good stewards of our funding resources,” i.e., taxpayer dollars.

The prototypes might remain in place if they are aesthetically pleasing and otherwise meet local needs in San Diego, he added.

“If they add to the infrastructure in the San Diego area in a beneficial way, we can keep them. If not, we can move them elsewhere,” he said.