Magnetic couplers for for fixed rakes of Mk2 coaching stock. These will require you to purchase 2mm x 1mm N52 Rare earth magnets and install them taking note of magnet polarity. Couplers simulate buckeye and associated air hoses. In order to traverse layout curves I would recommend the removal of the coach buffer heads from the shanks and to cut back the shank before re-gluing the heads back on to represent the coach buffers in their prototype retracted position.
These are the electro version of these couplers which allow you to add phophur bronze strip to the larger coupling heads to provide electrical connection between coaches.