in a plane perpendicular to the plane of the wire element 1 but in which the degree of flattening of the flattened ends 3 varies over their length fig3 b shows a second variant of the third embodiment in which the degree of flattening of the flattened ends 3 varies over their length the degree of flattening is smaller at the bending points or bends of the z shaped ends 3 than in the immediately adjacent portions of the bends fig4 through 7 show longitudinal cross sections of four different embodiments of steel wire elements 1 with l shaped ends 3 fig4 shows a fourth embodiment of a steel wire element 1 according to the invention the difference between the embodiment shown in fig1 and the embodiment shown in fig4 consists in the fact that the z shaped ends 3 are now replaced by l shaped ends 3 in which the l shaped ends 3 are bent in opposite directions fig5 and 7 show further embodiments of steel wire elements 1 with flattened l shaped ends 3 in which however the flattened l shaped ends 3 are provided with additional end structures to further increase the bonding in the concrete it is clear that numerous other variants are also possible within the scope of the invention the invention will now be further explained on the basis of the tests that have been carried out on four different types of steel wire fibers 1 with z shaped ends the four types are basic type b or steel wire fiber with z shaped.