Auxilia shields what options are there?

[Paullus Scipio]

Many thanks, Peroni, and others. One point of note that may help the identification of the shield design is that the figure on the Column seems to have a 'paintbrush' crest - otherwise only seen on Praetorians on the Column IIRC - I will have to check.....perhaps indicating Guard status .. Against this, a Trajanic frieze seems to show two cavalrymen guards with hexagonal shields - one with the scorpions often identified with Praetorians/Guards and the other with a thunderbolt design which are often taken to indicate that one represents Praetorian Guard Cavalry and the other Equites Singularis, but as to which is which.......