Metal Whisker Magne-Matic Coupler Short (1/4") Centerset ShankThe 153 "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 153 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 23, 33 or 43 coupler which will allow the modeler to remove the existing 23, 33 or 43 coupler and replace with the new smaller coupler. The 153 coupler is made of the same metal as the 43 for strength and rigidity.It is not recommended to use a metal coupler directly on a metal surface or in a metal draft gearbox to avoid possible electrical crossover and shorting that may cause damage. Use the provided insulated gearbox.Two pair per package.Package Includes:(2) Pair 153 Scale Whisker® Metal Couplers - Short Centerset Shank(2) Pair 242 Snap-Together Gearboxes(2) 625 Knuckle SpringsFeatures:Material - MetalShank Length - Short (1/4") (center hole to back of coupler head)Coupler Offset - CentersetKnuckle Spring - 625Centering System - Whisker®Head - Scale HeadWorks In Place of - 23, 33 ( 143 in a 252 box), short centerset "clone" couplersWorks With - 213, 232, 234, 242, 252, 262, manufacturer cast-on draft gearboxesMounting Specifications:Mounting Height - 25/64"Centerline - 25/64"Trip Pin Height - 1/32"Center Hole - 2-56 Insulated Screws are the most commonly used. (Screw length will vary)