BikeChickwrote a review of Shimano Dura-Ace CN-7900 Chain on April 20, 2009
I installed this chain when I replaced some 7800 series parts (rear der., cassette). I kept my 7800 front derailleur and R700 compact crankset. Immediately upon pedaling with new setup I heard a repeating clunk in the area of the cassette. Mechanic inspected and found the master link was making the noise. Seemed not to go through rear derailleur sprockets cleanly. He replaced with Wipperman link and it is all fine. He later told me Shimano suspended the 7900 master link production. Check it out for yourselves.