Passenger cars can be equipped with truck mounted couplers using the correct conversion bolster attachment. Truck mounted couplers permit closer coupling on radii down to 18" without causing binding for most passenger cars. Non-Magnetic trucks should be used with Kadee? Magne-Matic? Couplers. Wheels should be changed on AHM and Athearn trucks. Use Kadee? #521 or #522 non-magnetic wheels. Each kit contains a pair of Draft Gear Boxes, one pair of #5 Couplers, #634 Centering Springs, screws, special bolsters and instructions.