Why the brand matters more than it looks like it should
Racking is a structural system, not a set of parts. A beam is engineered for a particular frame’s connector, at a particular load, and the capacity figure on a load sign belongs to that combination. Mixing components from two systems because they physically clip together is one of the more common ways a warehouse ends up with racking nobody can put a defensible capacity on.
It also drives cost. If you can name your system, you can buy compatible components, extend a run, or replace a damaged upright without replacing a bay. If you cannot, you are pricing a rebuild.
And it decides your options when you move. See relocating or reconfiguring racking for what brand identification changes about a warehouse move.
The names you will actually encounter
Australian suppliers consistently list the same set: Dexion, Colby, Stow, Schaefer, APC, Macrack, Spacerack, Brownbuilt and BHD (also sold as Meca) — plus a substantial "Dexion-compatible" aftermarket that exists precisely because Dexion was dominant for long enough to become a de facto pattern.
The pages below take them one at a time: what the system looks like, how to recognise it, what is still available new, and what the second-hand market for it is like.