Metal Whisker Magne-Matic Coupling Medium Centerset 158 Scale All Metal Self Centering Whisker® Magne-Matic® Coupler Medium 9/32in Centerset Shank with 242 draft Gearboxes 2pr - Kit.The 158 "Scale" All Metal Self-Centering WHISKER® Coupler features a "Scale" Metal Coupler (a smaller head coupler which is more to scale and is patterned after the type 'E" couplers) & Metal WHISKER® Centering Spring, insulated Draft Gear Box and Lid.The 158 Coupler may be mounted with the supplied 242 draft gear box, other Kadee® HO-Scale draft gear box shown below or with the Manufacturers cast-on coupler pockets.The coupler will couple and uncouple with other Kadee® HO and HOn3 couplers. The coupler has the same shank length as the NO.5®, 28, 38 or 58 coupler which will allow the modeler to remove the existing NO.5®, 28, 38 or 58 coupler and replace with the new smaller coupler. The 158 coupler is made of the same metal as the NO.5® & 58 for strength and rigidity.It is not recommended to use a metal coupler directly on a metal surface or in a metal draft gear box to avoid the possible electrical crossover or shorting that may cause damage. Use the provided insulated draft gear box.The 158 package contains two pair of the new coupler and two pair of the 242 gearboxes, and instructions.