This 72-inch racking beam is constructed of high-grade steel for increased strength. The bracket tabs on the steel racking beams fit into the tapered slots on the welded end frame (sold separately). A rubber mallet (not included) may be required to help drive the beam bracket tabs into the slot to secure the beams. The particleboard or wire shelves (sold separately) rest on the stepped surface on top of the beams for easy assembly. Tie bars (sold separately) attach to the beam and provide additional strength and durability.