The Trump administration is officially backing off a campaign promise.
"I'll tell you what it's going to be made of: It's going to be made of hardened concrete, and it's going to be made of rebar and steel," President Donald Trump said at a rally in December 2015.
U.S. Customs and Border Protection is now considering "other designs" for the border barrier.
CBP updated its proposal page and said it might release two separate requests for proposals, or RFPs: One would be for concrete wall designs, and one would be for other materials.
The update might not come as a surprise. In an interview on CBS' "60 Minutes" last year, Trump hinted at making at least part of the barrier from something other than concrete.
"For certain areas, a wall is more appropriate ... but a fence will be, yeah, there could be some fencing," Trump said on CBS' "60 Minutes."
The announcement comes as the administration faces pushback over the rumored cost of the project. Republican leaders have said it'll cost between $12 billion and $15 billion, but other analyses pin the cost at nearly double.
CBP didn't give a specific reason for the change. Over 600 parties have registered interest in designing the border barrier so far.