the retaining collar 55 is formed there there is then in turn partly a widened portion 12 at its radial end this widened portion 12 extends in the circumferential direction around the tube element 13 the widened portion 12 is formed in the shape of a ring segment on the tube element 13 and represents the one of two coupling sides of a fastening system 4 fig1 the widened portions 12 are designed in such a way that the l shaped steps 20 fig3 of the component 1 can enclose them fig3 shows the underside of the component 1 e g turbine blade the second coupling side 16 of the fastening system 4 being formed on this underside on the underside of the component 1 which bears against the holder 7 there is a shaped element 34 corresponding to the shaped element 25 for example a recess 34 in which the correspondingly shaped bolt lug 25 fig4 engages in a positive locking manner in such a way that the bolt lug 25 cannot rotate in the receptacle 34 as viewed in the circumferential direction around the radial axis 3 l shaped steps 20 are formed on the underside of the component 1 the l shaped steps 20 have at least one lead through 17 into which the widened portions 12 of the tube element 13 fit the l shaped steps 20 are designed in such a way that the component 1 can be rotated in such a way that the widened portions 12 can be arranged bayonet like inside the l shaped steps 20 after it has been appropriately rotated the turbine blade 1 is held in radial direction 3 by the l shaped steps 20 and the widened portions 12 fig4 shows the bolt.