I make all my own. I use Berkley nylon coated stranded leader wire. You can get it all the way from 20 # to over 100# breaking strength. Most planes get by nicely with 30 to 60# line. They also sell the crimping ferules which you can easily crimp with a set of dikes or other crimping tool. I never attach directly to the servo, I always make a pulley about a.5 to 2.5 inches in diameter and mount it withing about 4 inches of the servo. The line to the moveable surfaces then goes around this pulley and back. You need to anchor it to the pulley so that it doesn't slip. I then use a very stiff short arm from the servo to the pully using ball link hardware. Do not, repead