The Chiappa Rhino 60DS is a double-action magnum revolver. The weapon takes .357 Magnum ammunition which is used in a 6 round cylinder.
In her service to Task Force X, Harley Quinn is shown to carry at least two different weapons. One being her personalized baseball bat named Good Night and the other being a customized black Rhino 60DS with a white grip and golden decorations on both the grip and main body. The body has her initials on it and the cylinder has the alternating words "Love" and "Hate" on it.
She carries the revolver in a black leather holster slung under her arm.