The US wants to build a 30-foot border wall that looks appealing from the north side and is difficult to climb or cut through, according to contract notices posted to a government website.
They further detail President Donald Trump's promise to build a "big, beautiful wall" at the Mexican border.
The notices were made public on Friday by Customs and Border Protection (CBP), the Homeland Security Department agency that will oversee the project and eventually patrol and maintain the wall.
The proposals are due to the government by March 29.
One of the CBP contract requests calls for a solid concrete wall, while the other asks for proposals for a see-through structure.
Both require the wall to be sunk at least six feet into the ground and include 25 and 50-foot automated gates for pedestrians and vehicles.
The proposed wall must also be built in a such a way that it would take at least an hour to cut through it with a "sledgehammer, car jack, pick axe, chisel, battery operated impact tools, battery operated cutting tools, Oxy/acetylene torch or other similar hand-held tools".
The government will award a contract based on 30ft wide sample walls that are to be built in San Diego.
This is the latest step in the Trump administration plan to build a border wall.
Last month CBP put out a call for "concept papers" to design and build prototypes by March 10. Mr Trump has bragged in recent days that the wall is ahead of schedule.
The government has not said where the wall will be built, though the contract notices suggest some pieces of a new wall could replace existing fencing that stretches over about 700 miles of the roughly 2,000-mile border.
The current fencing of mixed construction, including 15ft steel posts set inches apart that are designed to keep people from crossing and shorter posts that are intended to block cars. Border Patrol agents are constantly repairing holes in the structure.