The Rebco ROTRXN Running Tool is functionally identical to the ROTRX in all operational respects; it runs, locates, and sets the same types of Lock Mandrels across the same size range. The single distinguishing difference is that the ROTRXN uses Retainer Dogs in place of the Lugs used by the ROTRX to physically attach the lock mandrel to the running tool during the trip downhole. This mechanical difference in the attachment interface makes the ROTRXN the correct selection when the specific lock mandrel assembly being installed is designed for retainer dog-style engagement rather than lug-style engagement — a detail determined by the lock mandrel manufacturer's specification. Operators should confirm the mandrel attachment interface before selecting ROTRX or ROTRXN for any given job.