... phosphor,bronze and so on.wire pulling springs are new design springs Industry's second most commonly used springs, extension ... uses. Extension springs are most notable by their closed coil design and hooked ends. MaterialPiano wire, stainless steel, High Carbon ... position.LoadOur computer can assist you figure out the load design.Style of Endshalf loop / full loopSurface FinishNickel / Zinc / Gold / ...