This is the TP200 standard force (SF) stylus module #A-1207-0010.
The stylus module carries the M2 stylus mount and provides overtravel in the X, Y and +Z probe axes. Overtravel in the -Z probe axis is accommodated by separation of the module from the probe body.
The module houses the mating half of the magnetically held kinematic coupling which ensures repeatable positioning on the probe body. The coupling consists of three bearing points formed by the V grooves on the rear of the stylus module, which seat on three ball bearings located on the front of the probe body. The fourth V groove and semi-recessed ball form an alignment feature to ensure that the module has a unique orientation in the rotational axis.
The module and stylus axis will be visibly misaligned if the coupling is not correctly seated. Alignment symbols are provided to assist manual alignment. The module cover forms a sliding ring which transfers excess force to the case of the probe body if the maximum Z axis overtravel distance is exceeded.