Black Diamond Stoppers are time-tested climbing nuts, with a direct link from the original chocks.
Whilst perhaps not quite as popular as Wild Country Rocks or DMM Wallnuts, the BD Stoppers do provide a good alternative or make a great second climbing nut set, as they are fatter and squarer allowing you to cover more options for potential placements.
With the full range of Stoppers you end up with plenty of smaller wires due to their sizing (roughly a Black Diamond Stopper 5 is equivalent to a size 2 Rock/Wallnut).
Durable aluminium heads and steel cables
Transverse taper is versatile in flares, constrictions and parallel cracks (smaller sizes are straight for better surface contact)
Rounded edges for easy cleaning and reduced snagging