Originally Posted by Racing Dan

As far as i can tell from the picture the elongation amounts to 4mm. Assuming its whole chains they are each more than 100 links and at least (100*25,4)/2=1270mm length. Thus, true elongation is only (4/1270)*100=0.3% (!) - Can you verify this?

Imo all three gauges are wrong and flag the chain prematurely, if 0.5% is the gold standard. And 0.5% is only 1/2 the usual engineering standard of 1%.