Shipping Container World: "The $50 Part That Holds Your House Together. We always talk about big cranes and welding, but this little piece of metal is the real MVP of container architecture. This is a Twist Lock. The Mechanism: In the top right photo, you see the device itself. It looks simple, but it is designed to withstand hurricane-force winds and massive waves at sea. The Connection: In the top left photo, you see it placed into the "Corner Casting" of the red container. Every shipping container has these holes in the corners. The lock goes in, you stack the next container on top, and then... The Lock: In the bottom photo, you pull that metal lever. Click. The internal cone twists, locking the top white container to the bottom one instantly. No welding required. It’s exactly like Lego, but for adults. Small part, massive strength.