Abstract: A device for influencing the wake flow of an aircraft wing having a high pressure side and a lower pressure side, the device including a body adapted for attachment in the region of the tip of the aircraft wing and having a through-duct with a first opening at a first end of the duct being located on the high pressure side of the wing and a second opening at a second end of the duct being located on the low pressure side of the wing, the duct being configured to permit a fluid flow through the duct so as to inhibit the flow of the fluid around the outboard extremity of the wing and to direct the fluid flow through the duct into a pair of opposing rotating flows of substantially equal magnitude externally of the duct.