This is 20 Pairs of Kadee® #5 Universal Magne-Matic® Couplers. FEATURES: Precision engineered. These couplers are interchangeable with Kadee® 20, 30 and 40 Series couplers. Simple drop-in design to accommodate manufacturers" draft gear boxes and cast-on coupler pockets. #5 medium centerset shank metal couplers. Plastic, insulated draft gear boxes. Bronze centering springs. Side and center screw mounting holes. The most functional & reliable knuckle couplers on the market! Very detailed instructions. Made in the USA. INCLUDES: (40) #5 Couplers (40) #5 Draft Gear Boxes & Covers (42) Centering Springs (24) Knuckle Springs REQUIRES: Assembly Coupler Pliers (KADU0237) Hobby File Grease-em (KADU0231) SPECS: Scale: HO 1:87 COMMENTS: Also available fully assembled (KADU0003) kr9/8/06