N GUAGE .RARE. RAPIDO COUPLERS ARE BULLET PROOF RELIABLE FOR COUPLING.  EASY TO REMOVE OR SUBSTITUTE REAR OBS COUPLER.  TO CHANGE OUT RAPIDO COUPLERS MY FAVOURITE IS FIRST GENERATION KATO MANUAL KNUCKLE COUPLERS AVAILABLE ON EBAY INEXPENSIVELY FROM JAPAN. THEY ARE EASY TO ASSEMBLE THE TWO PARTS, AND SLIDE INTO THE COUPLER POCKETS WITHOUT SPRINGS.