Once the patent on Sun Tour's slant parallelogram derailleur expired, both Shimano and Campy came out with their own versions. Today Campy and Shimano are billion dollar companies and Sun Tour is in the bone yard. It's an old story. When Edison died, he was one of the richest men in the world. When Tesla died, he was about to be evicted for non-payment of his rent........the FBI showed up and hauled off his papers. Tesla would have been buried in an unmarked grave in potters field had not the Yugoslav embassy paid for his funeral.