On September 3, the gun control group founded by Gabby Giffords and Mark Kelly began running ads against Martha McSally (R-AZ)–a retired Air Force pilot seeking to fill the congressional seat Giffords herself once held.
Check it out:

McSally, who was “the first female Air Force pilot to fly in combat,” is being targeted by the group because she is pro-gun. She is running against Representative Ron Barber (D-AZ), a gun control supporter who won Giffords’ old seat in a 2012 special election.

According to Politico, the ad criticizes McSally’s opposition to gun control–particularly universal background checks–by suggesting she supports a “loophole that allows criminals and the dangerously mentally ill to buy guns without a [background] check.”