Probe unit and holder for a probe unit

A probe unit (27) for a measurement apparatus (20) configured to detect a measurement value at a measurement location of an object surface (21) in a contacting or contactless manner, the probe unit (27) comprising:

• a support (28),
• a probe element (29) arranged on the support (28) that is configured for probing the object surface (21) in a contacting or contactless manner,
• a mounting device (31) provided on the support (28) that is configured to be mechanically connected with a holder (26) of the measurement apparatus (20), wherein the mounting device (31) comprises a contact unit (32) that defines a first longitudinal axis (L1) and that is configured to abut against a counter-contact unit (51) of the holder (26) of the measurement apparatus (20) in a contact position (P) so that a rotational degree of freedom in a circumferential direction (U) around the first longitudinal axis (L1) remains between the mounting device (31) and the holder (26), and wherein the mounting device (31) comprises at least one mounting magnet (40, 41, 42) that is configured to cooperate with at least one holding magnet (55, 56, 57) in the contact position (P) so that a magnetic axial force (FA) parallel to the first longitudinal axis (L1) is created between the mounting device (31) and the holder (26) and that a magnetic circumferential force (FU) in a circumferential direction (U) around the first longitudinal axis (L1) is created between the mounting device (31) and the holder (26) until a predefined rotational position (R) around the first longitudinal axis (L1) is reached between the mounting device (31) and the holder (26).