Comparison - Hirose DF40C vs DF40HC

What is the difference between the DF40C series and DF40HC series from Hirose?

The DF40C was the original product offering and only offered stacking heights of 1.5mm-2mm. The DF40HC was added to the product line later to offer more stack height choices and applies only to the female receptacles.The addition of the DF40HC receptacles added stack height options of 2.5mm - 4mm to the original 1.5mm-2mm options.