Strike-slip faults are affected by many variants, which do not remain constant along the strike. The most common factors are differences in the rate of displacement and the width of shear zone. A study of these variants on the Nehbandan dextral strike-slip fault in east Iran has been done and the experimental models shows that the maximum displacement and width of shear zone occurs in the central part of strike - slip faults. But the displacement decreases exponentially toward the termination of faults. The relationship between these two factors can be formulated as Y = C.e γ ^d. The γ ^d coefficient in the terminal splays is smaller than in the main fault. These can be seen on experimental models, which have been done by flexy-glass materials. Comparison between displacement - distance and width of shear zone-distance curves from the field traverse (Nehbandan data) and experimental materials (flexy-glass) shows the experimental curves are symmetry but the "natural" curves are asymmetrical. This difference is due to homogeneous nature of manufactured materials while the earth's crust is heterogeneous.