Abstract: The inventive apparatus may be slid onto a guiding catheter or other thru-lumen catheters, solid catheters, such as Electrophysiology catheters and multi-lumen tubing and advanced to the distal end of the guiding catheter or other thru-lumen catheters, solid catheters, such as Electrophysiology catheters and multi-lumen tubing to assist in holding the distal end of the guiding catheter or other thru-lumen catheters, solid catheters, such as Electrophysiology catheters and multi-lumen tubing at a target location within a patient, by utilizing an externally applied magnetic field to hold a plurality of magnetic elements on the apparatus in alignment with the target location. A medical device may then be advanced through the guiding catheter, for example, to the target location in the patient, without the guiding catheter backing out.