The South African Infantry Brigade was badged rather unusually. There were in fact four different South African Infantry Regiments in World War One; 1st, 2nd, 3rd and 4th. They all shared the same cap badge, but had differing collar badges to distinguish one from the other. The badge chosen for these regiments was circular in shape and depicted the head of an antelope. This badge was updated slightly between the wars and today we are looking at a World War II example:
Around the edge of this badge is the legend ‘Union is Strength’ in English and Afrikaans. It was the exact Afrikaans wording that changed between the wars, going from Eendracht Maakt Macht to eendracht maak mag in 1928.
In reality then, this badge was more of a divisional or brigade badge than a regimental badge, and the only way to distinguish between the different numbered regiments was insignia on the uniform rather than the cap.
The rear of this badge has two securing lugs and a cotter pin to attach it to a cap:
The badge was worn on a variety of headwear, including the tam o shanter, peaked service dress cap and slouch hats. I suspect that this may in fact be an officers example as it appears to be bronze. I have seen some plain brass examples, which were presumably for other ranks but it is not clear as some SA units seem to have issued bronze style badges to all their troops, regardless of rank.