A tool for use with is configured with a tool centering element and a fastening portion with form-locking elements for axial mounting and fastening onto a drive shaft of a hand-held power tool. The drive shaft is drivable in oscillating fashion and the centering element centers the tool relative to the drive shaft. The tool form-locking elements define a rotary position of the tool relative to the drive shaft. The centering element may be a through-hole in a fastening portion of the tool or, may be a fastening screw that passes through an axially centered through hole in the fastening portion to the tool for securing the toll and fastening screw in a bore within the drive shaft to which the tool is attached for intended operation.