One of America’s toughest immigration hard-liners apparently keeps a model of a border wall in his office.

Rep. Steve King (R-Iowa) tweeted a photo Friday that showed the model, as well as retired Gen. John Kelly, President-elect Donald Trump’s nominee for secretary of homeland security, with whom King was meeting.

Excellent Trump appointment for Secretary of Homeland Security, General John Kelly & I discuss border security with my wall model on table. pic.twitter.com/OGkBcN6NjU — Steve King (@SteveKingIA) January 13, 2017

Hopefully Kelly seeks out other opinions.

The model in King’s photo appears to feature thick, opaque slabs topped with barbed wire. It’s visually impressive. But there would a big problem for anyone tasked with patrolling that wall: You can’t see through it.

Modern sections of wall erected along the U.S.-Mexico border are often made of thick steel beams called “bollards,” spaced at short intervals. This kind of barrier is more of a fence than a wall, but is just as difficult for a person to pass through.

A fence may seem less grandiose than a wall, but it’s more practical. If the wall is opaque, agents can’t see who’s trying to cross. More importantly, they can’t identify potential threats.

In the days before the 2016 election, The Huffington Post took a tour of the border around Nogales, Arizona, with John Lawson, a veteran Border Patrol agent. Lawson told us that when he started out, the primitive fence was opaque. That was a liability for agents, and sometimes a hazard. In some instances, he said, assailants would scale the wall and try to drop cinder blocks on the agents’ vehicles as they passed below.

“You need to make a fence you can see through,” Lawson said ― a remark that wasn’t aimed at any public official in particular, and that occurred months before King tweeted his photo of the model wall.

When U.S. Customs and Border Protection asked for funds last year to erect additional miles of barrier along the country’s southern border, it requested metal and concrete bollard fencing specifically, according to Reuters.

FREDERIC J. BROWN via Getty Images This section of border fencing in Nogales, Arizona, is built of a series of metal beams, which allows Border Patrol agents to see through it.

King’s office did not respond to a request for comment.

The Iowa Republican has distinguished himself as a vocal opponent of immigration, advocating ideas like making English the official language of the United States and proposing legislation to end birthright citizenship.

But his district lies several states and more than 1,000 miles away from the U.S.-Mexico border. Sometimes it shows.