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 at least one magnet in a magnet recess. The at least one magnet may include a first and second conductive region, where the first conductive region is a fixed, first radial distance from a center point of the inner cavity and the second conductive region is a second radial distance from the center point of the inner cavity. A shaft recess of the conductive shaft aligns with the magnet recess when the conductive shaft is inserted into the inner cavity and an electric circuit detects whether a metal ring is secured around the conductive shaft in response to simultaneous contact between: the metal ring and the at least one magnet and the conductive shaft and the electrical contact.