Ron, Kuerassier are heavy cavalry and, as noted above, they wore a cuirasse or full breast and back plate although this armor may have been dropped from field use by WWI. These fellows were even further distinguished by their steel or tombak lobstertail Pickelhauben. The most famous of these units were the Saxon Garde du Korps and the Prussian Garde du Korps; both wore tombak cuirasse and lobstertail the lobster tail was topped with a rampant lion in the case of the Saxons and a crowned eagle in the case of the Prussians.
Real nice for Potsdam military reviews but not of much value by August of 1914. The french, Austrians and Russians also fielded the same class of cavalry.