Male Ring-necked Ducks are bold black-and-gray ducks with a dark head, black back and gray sides.
Females are rich brown with a contrastingly pale cheek and a whitish eyering.
Both male and female have a grey bill with a white band and a black tip.
Despite the name, the ring on the neck is almost never visible.

A male. Ascarate Lake, El Paso, Texas, USA, 18 January 2019