Medium-duty keyhole-slot cantilever rack uprights can support moderately heavy materials such as pipe, tubing, lumber and bar stock. They accept compatible arms, and they do not require special tools or bolts to attach the arms to the uprights. The arms slide into keyhole slots on the uprights, and the slots have a tapered bottom that keeps the arms from coming loose as items are moved onto or off of the racks.

Heavy-duty pin-lock cantilever rack uprights can support heavier materials than medium-duty cantilever rack uprights, such as heavy bar stock, tube stock, and sheet material. They accept compatible arms, and they do not require special tools or bolts to assemble the arms to the uprights. The arms attach to the uprights with a locking pin that holds them securely in place.