Start a run of shelving with one Starter unit and attach an Adder Unit to it. Many Adder units can be attached to the first Adder unit. It's strong, simple, easy to install, and inexpensive.
Use an Adder unit to turn a corner at a right angle. An added benefit is that by configuring this way, you eliminate a corner post, allowing barrier-free access to stored goods in the corner of the shelving unit.
Adder units may be installed onto any wire shelving unit at a right angle. This allows you to eliminate two corner posts, creating unencumbered access to maximize storage opportunities.