What becomes clear traversing the US-Mexico border is that the current wall varies quite a bit. That's why it's unclear exactly how President Trump wants to use the more than $5 billion he's requesting to build a new barrier.
Points-of-entry and cities have hardened high-tech barriers using thick wire, sensors, and are regularly patrolled by U.S Customs and Border Protection.
Rural areas have different types of border wall ranging from simple barb wire fencing to welded railroad ties. Near the Santa Teresa point-of-entry, construction was recently completed on the steel-slat bollard wall. This wall ranges in height from 18-30 feet.
The 20-mile stretch was erected at a cost of $73 million dollars. The barrier at this location is the type of wall that Trump has referenced specifically in his tweets. He has presented this as an alternative to a concrete wall.
It is also currently unclear if any of the funding would be allocated for ancillary measures related to the wall like studies on environmental impact. What is clear is that, regardless of the compromises made to end the government shutdown this issue will remain contentious.