Inexperienced fits a file that can easily withstand twisting.
In general, the more its resistance to cyclic fatigue, the less its resistance to torsional fatigue,due to the inherent properties of martensitic materials- High strength and rigidity.However, Rogin Super Flexi Files can easily withstand torsion.
As you can see in this video, Super Flexi Files works very gently and cuts well,Ideal for inexperienced users.