A cochlear implant system, comprising: a subcutaneous housing containing electronics for at least stimulation or collection of data and at least one antenna for communicating with an external device, the subcutaneous housing including a main body having a U-shaped radial cross-section, a bottom cover secured to the main body, forming a hollow cavity bounded by an inner surface of the main body and the bottom cover, and a central cavity in a center of the subcutaneous housing formed by a portion of an outer surface of the main body, characterized in that the central cavity comprises a a ledge; a magnet removably inserted into said central cavity includes a cylindrical body with a central axis, the central axis aligned with a removal axis of the central cavity, a groove extending circumferentially around the cylindrical body, and a top surface, the top surface including an outer edge, a plurality of ribs extending radially farther than the outer edge, and a plurality of abutments extending radially farther than the ribs; and a compressive ring seated in at least one of the groove of the cylindrical body or in the ledge in the central cavity;, wherein the compressive ring engages the groove and below the ledge when the magnet is inserted into the central cavity and biases the magnet against removal from the central cavity. a subcutaneous housing containing electronics for at least stimulation or collection of data and at least one antenna for communicating with an external device, the subcutaneous housing including a main body having a U-shaped radial cross-section, a bottom cover secured to the main body, forming a hollow cavity bounded by an inner surface of the main body and the bottom cover, and a central cavity in a center of the subcutaneous housing formed by a portion of an outer surface of the main body, characterized in that the central cavity comprises a a ledge; a main body having a U-shaped radial cross-section, a bottom cover secured to the main body, forming a hollow cavity bounded by an inner surface of the main body and the bottom cover, and a central cavity in a center of the subcutaneous housing formed by a portion of an outer surface of the main body, characterized in that the central cavity comprises a a ledge; a magnet removably inserted into said central cavity includes a cylindrical body with a central axis, the central axis aligned with a removal axis of the central cavity, a groove extending circumferentially around the cylindrical body, and a top surface, the top surface including an outer edge, a plurality of ribs extending radially farther than the outer edge, and a plurality of abutments extending radially farther than the ribs; and a cylindrical body with a central axis, the central axis aligned with a removal axis of the central cavity, a groove extending circumferentially around the cylindrical body, and a top surface, the top surface including an outer edge, a plurality of ribs extending radially farther than the outer edge, and a plurality of abutments extending radially farther than the ribs; and an outer edge, a plurality of ribs extending radially farther than the outer edge, and a plurality of abutments extending radially farther than the ribs; and a compressive ring seated in at least one of the groove of the cylindrical body or in the ledge in the central cavity;, wherein the compressive ring engages the groove and below the ledge when the magnet is inserted into the central cavity and biases the magnet against removal from the central cavity.