A formula delivery appliance can be used for treatment of the hair and scalp, such as an appliance used to color hair. The appliance may include a consumable assembly incorporating various components of the hair and scalp treatment appliance, a portion of which may be consumed and then replaced by a user. In this regard, the consumable assembly may include one or more formulation delivery packets, nozzles, manifold chambers, distribution protrusions, and the like. The hair treatment appliance may also include a rotatable coupling having a driven gear and a drive gear, where the driven gear may selectively engage the drive gear. In another aspect, the hair treatment appliance may also include a fluid container to retain a volume of formulation for delivery to the appliance.