Greater resistance to cyclic fatigue and higher flexibility.
Use SX to open canal, set up a straight path;Irrigate, then expand a glide path by PATH FILE #12.5, or #15, or#20.
Use S1 to prepare to 3mm or 4mm SHORTER than the working length.(even shorter) ; Use S2 to prepare to working length.
According to the preparation status, to choose use F1- - F3 to prepare to working length Everytime you change file, please ensure irrigate the root canal copiously and frequently with a lubricants, such as EDTA. (very important!!)