This is 2 Pairs of Kadee?? 148 Magne-Matic?? "WHISKER" Metal Couplers.FEATURES: Precision engineered. Simple drop in design. Metal medium (19/64") centerset shank. The 148 coupler will work anywhere a 5 Coupler will work. It"s a direct replacement for most Bachmann On30 couplers and a direct replacement for any plastic Medium Centerset "clone" couplers. Can be mounted using the included draft gear box or with manufactures" cast-on coupler pockets. Metal couplers and built-in "Whisker" centering springs. Insulated draft gear box and covers. May be mounted from the top or mounted from the bottom. Bronze centering springs. The most functional & reliable knuckle couplers on the market! Very detailed instructions. Made in the USA.INCLUDES: (4) 148 Couplers (4) Draft Gear Boxes & CoversREQUIRES: Assembly Coupler Pliers (KADU0237) Hobby File Grease-em (KADU0231)SPECS: Scale: HO 1:87KadeePart KAD148