A towing shackle, also known as a tow shackle or D-ring, is a device used for towing or recovering vehicles. It is a small, sturdy piece of hardware that is typically made of metal, such as steel or aluminum. The shackle consists of a loop or D-shaped ring with a pin or bolt running through the center. The shackle is used to connect the tow vehicle to the vehicle being towed or recovered.