An apparatus and method for determining whether a conductive ring is attached to an electrically conductive shaft. The body of the apparatus includes an electrical contact and side magnets positioned in a recess along the circumference of the cavity. When the shaft is received by the body, the electrical contact is in contact with the conductive shaft and the side magnets in the recess are in contact with the ring attached to the shaft, if present. An electrical signal is provided to the shaft and ring via the magnets and an output signal is generated. The output signal is indicative of whether the ring is attached to the shaft.