This odd device was authorized as an attachment to the suspension ring of 1870 2nd Class Iron Crosses in 1895 on the 25th anniversary of the Franco Prussian war.
Naturally, the numbers of recipiens of that decoraation who were still wearing a uniform in 1916--when the 15mm size ribbon bars came into general use-- was remarkably small.
There are many fake cast versions of this device, often ludicrously "dressing up" ordinary WW1 ribbon bars. Remember that every veteran of 1870 was entitled to the 1897 Wilhelm I centenary Medal, so any 1915+ ribbon vbar without THAT solid yellow ribbon is an immediaate tip-off that something is wrong.
So I am glad to be able to present a struck piece that is right, courtesy of stogieman.