Image Item No. Description  x547b  Magnet Coupling, Train - 6.5mm Cylinder Catalog: Parts: Magnet  x547a  Magnet Coupling, Train - 7.5mm Cylinder Catalog: Parts: Magnet  x547c  Magnet Coupling, Train - Long Cylinder (8 mm) for Train, Base 6 x 22 Catalog: Parts: Magnet  x547c  Magnet Coupling, Train - Long Cylinder (8 mm) for Train, Base 6 x 22 Catalog: Parts: Magnet