"Greatest Weapon" and "Under The Water" are Duffy's first Hand Habits releases since June's "motherless", and are both released via Psychic Hotline, the label founded by Sylvan Esso's Nick Sanborn and Amelia Meath.

The first of the two tracks was written by Duffy and Ethan Gruska, and features additional vocals from Sanborn and Meath, while "Under The Water" sees Meath take the lead on vocals, while Duffy plays guitar.

Stereogum reports that Duffy said of "Under The Water", "I wrote it all in one go. Learning how to hold my head underwater when I was a kid was a moment of independence that I hadn’t been expecting - all of the sudden I was able to be completely alone in the pool - even when I was surrounded by people."