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 Smooth Fine Detail and Smoothest Fine Detail plastic and are the most highly detailed South African bogies on offer in HO Scale for 16.5mm track gauge. They include accurate bolster profiles and brake rigging. They require M2 screws for fixing and Atlas 33" wheelsets (#180100).