Dunlop Jazz III black plectrums are a popular pick among guitar players because of it is small and has a sharp end. The small size of the black Jazz III pick means the thumb makes more contact with the string. Therefore the guitar player has more control over the string.
For some guitar players, having a plectrum that allows more contact to the string is a great thing. For others, it is something they would rather avoid.
The Black Dunlop Jazz plectrum is just one of many of the different types of Jazz III guitar picks available in the Jim Dunlop range.
If the black Jazz III is too stiff for you, try the Red Jazz III guitar pick