Widely used, C-130, Jetstar, S-3, C-141, 747, 1011, DC-10, helicopter rotor blades. Since 1981 Boeing has supplied tungsten weights as replacements. Rescued the crews of two Wessex helos that clipped blades during formation flight, and finding the DU weights which had been spread about the countryside was of some concern to management. Wessex was a licence built H-34 which came into production in 1954, presumably they used DU since that time.