Donald Trump's Mexican border wall will be nine metres high, difficult to cut through and look good - at least from the US side - according to documents posted online.
Customs and Border Protection, a division of Homeland Security that will oversee the wall's construction, is looking for companies to build the wall, which Mr Trump says will reduce the flow of "killers and rapists" into the US.
There are two proposals listed in the documents. One is for a solid concrete structure, the other see-through. To get the contract, companies will need to show their wall would take at least an hour to cut through using a sledgehammer, pick axe, chisel, carjack or acetylene torch.
Either way, the side of the wall facing the US has to be "aesthetically pleasing in colour".
While it's asked for nine-metre walls, the proposals admit a 5.5m wall may be acceptable - low enough for a skilled pole vaulter to clear.
It's the second time Mr Trump's administration have asked private companies to bid on building the wall, which the President wants to extend the entire 3110km border between the two countries.
Mr Trump has long insisted Mexico would pay for it, which Mexico has rejected. The estimated cost of building the wall is between US$15 billion and US$21 billion.