A bull ring (also known as a lashing ring or tie-down point) is a heavy-duty, reinforced metal ring or loop welded to the internal structure of a shipping container, typically along the bottom frame rail and/or the floor level.
The sole purpose of the bull ring is to serve as a strong, certified anchor point for securing cargo. Shippers and port workers connect chains, wire rope, or lashing straps from the cargo to the bull rings to brace the load, preventing any lateral or longitudinal shifting that could damage the cargo or the container walls during the rigors of ocean transport.