in the radial direction with respect to an outer circumference not described in greater detail of the outer sleeve 14 the inner sleeve 12 and the outer sleeve 14 can be provided as separate component parts however the inner sleeve 12 and the outer sleeve 14 are preferably pre assembled together so as to enable easier handling of the fastening apparatus 10 in the present case the inner sleeve 12 and the outer sleeve 14 are interconnected by a separable connecting portion 32 the inner sleeve 12 and the outer sleeve 14 are preferably produced from plastics material in this instance more specifically as a single element which is preferably produced in an injection moulding method the connecting portion 32 can be formed by a circumferential thin separable web 33 or by a single individual web 33 or a plurality of individual webs 33 distributed over the circumference and interconnecting the inner sleeve 12 and the outer sleeve 14 one or more radial recesses 34 can also be provided at the outer circumference 15 of the outer sleeve 14 and for example may perform the function of an anti twist protection and or may be used for attachment of a tool for example the radial recesses 34 may be used for positioning in an automatic assembly machine in particular if the outer part 14 and the inner part 12 are produced separately and are pre assembled together retroactively in an automated manner fig1 also shows a first anti twist protection portion denoted by 36 and is formed in the region of the inner circumference 17.