The prototypes for President Donald Trump’s proposed border wall along the U.S.-Mexico line have all been erected and are pending inspection from Customs and Border Protection, the Independent reported Saturday.

Trump has said he plans to inspect the prototypes himself and choose the one he likes best. Six companies were commissioned to create four concrete prototypes and four prototypes made of other materials. The prototypes were specifically designed to obstruct digging and climbing — they are between 18 and 30 feet high and extend six feet below the ground — and two of the models have a see-through component.

Officials asked for the prototypes to be able to withstand at least an hour of punishment from a sledgehammer, pickaxe, torch, chisel or battery-operated tool and to build in features that prevent the use of climbing aids such as grappling hooks.

The construction is set to cost $21.6 billion and take three years to finish, but Congress has not yet approved funding for the massive project. Five of the six construction companies bidding for the job are American-based and the sixth is ELTA, or Israel Aerospace Industries, one of Israel’s leading defense contractors.

Prototypes for Trump's Border Wall Hit Inspection Phase