I am much more impressed by racquet builders who carry over their racquet technologies from generation to generation. For example, I believe that the current range of Dunlops includes their new technology, Aerogel, but also includes the last two as well, MFil and Hotmelt graphite. In contrast, I am nonplussed by a company like Head, which just a few short years ago was attempting to convince us that Liquidmetal was going to revolutionize the game of tennis, but has since dropped Liquidmetal like a bad habit with the emergence of their next technology that will change the sport, Microgel. By carrying over technologies from one generation to the next a racquet builder communicates to the consumer that they actually believe that their technologies enhance their frames, and are worthy of using over the long haul. By dumping one technology after another for the next big thing, a racquet builder instead sends the message that their technologies are mere marketing ploys. Other than the switch from wood to graphite, what is the racquet technology that has had the longest legs?