CHICAGO -- McDonald's has just unveiled its latest product, but you can't eat it.
A new advertising campaign is promoting a straw that lets you sip two flavors of a shake at once.
McDonald's said a whole team of engineers designed the new straw. It was created for the shamrock shake - which has a layer of chocolate on the bottom and mint on the top, so you need "the straw" to taste both flavors.
"The straw" debuted on Facebook Live Wednesday.