This is a set of of *TWO* pairs of bogies - that is four bogies in total, enough for two wagons.
The South African Railways Aligned bogies visually looks like a cross between a Spoorbarber bogie and a Commonwealth bogie. Their basic structure is Spoorbarber-like, but they also have stabilisers similar to those found on Commonwealth bogies. They were used primarily under steam heat wagons, guards vans and the like.
This variant has a roller bearing axlebox
This set of four bogies is available in Frosted Extreme Detail, Frosted Ultra Detail and Acrylic and are the most highly detailed South African bogies on offer in HO Scale for 12mm track gauge. They include accurate bolster profiles and brake rigging. They require M2 screws for fixing and Steam Era Models 9.6mm diameter 12mm gauge wheelsets (WN4).
Note that the Acrylic prints use a different and slightly less detailed design (Still highly detailed though) than the Frosted prints due to material constraints.