The two leading presidential candidates meet in Las Vegas on Wednesday night for their third and final debate, and with Election Day 20 days away. Democratic nominee Hillary Clinton holds a 46 percent to 40 percent lead over the Republican nominee Donald Trump, according to an NBC News|SurveyMonkey Weekly Election Tracking Poll.

Previous debates have provided a small but sometimes important bump in the polls. Here's a breakdown for debate viewers.



   



 

When is it? Clinton and Trump will enter the University of Nevada, Las Vegas’ Thomas & Mack Center stage at 9 p.m. ET to debate six topics, with 15 minutes of discussion for each. In those 15 minutes, they both will receive two minutes to argue their points, and then can take two-minute turns responding to one another. There will be no commercials for the 90-minute debate.

Where can I watch? The debate will be broadcast live on all the major broadcasters: ABC, CBS, FOX, NBC, CNN, Fox News, MSNBC, and C-SPAN among others. YouTube also offers a plethora of live-streaming options here.

Who is Chris Wallace? The “Fox News Sunday” anchor, who has a reputation for challenging politicians on both sides of the aisle, has moderated Republican primary debates with colleagues Megyn Kelly and Bret Baier, and promises a “fair and balanced” exchange on Wednesday. The first Fox anchor to moderate a debate, Wallace told his employer on Tuesday, "If people say, 'it was a great debate and I don’t remember you being there,' I will have done my job."

What will Trump and Clinton talk about? Wallace also told Fox News his intended debate topics: immigration, the economy, the Supreme Court, “debt and entitlements,” “foreign hot spots” and “fitness to be president.” The choice of subjects was a bit more specific than Lester Holt’s selection of talking points for the first debate, which included only “America’s direction,” “achieving prosperity” and “securing America.”

No Gary Johnson? Because the former governor of New Mexico was polling at less than 7 percent less than a week before the debate—well below the necessary 15 percent threshold—he was not invited to join Trump and Clinton on stage for the final contest. Also absent will be Green Party candidate Jill Stein, who garnered an average of only 2.4 percent of national four-way contest polling votes, according to RealClearPolitics.