This is a Package of 25 Pairs of E-Z Mate Magnetically Operated Center Shank-Medium Knuckle Couplers from Bachmann. FEATURES: Coil springs are molded as an integral part of the coupler. Patent Pending Spring Retainers. Easy installation and operation. Fits most HO scale cars with built-in draft gear boxes (coupler pockets). Compatible with all magnetically operated knuckle couplers. These couplers are center shank-medium. Operate with a standard metal "glad hand" and under track magnet. Carded packaging. INCLUDES: One Package of 25 Pairs of E-Z Mate Center Shank-Medium Knuckle Couplers. REQUIRES: Under-Track Magnet HO Scale Train Equipment Adult Supervision SPECS: Scale: HO (1/87) COMMENTS: Keep away from children under 3 years of age due to choking hazard. sdw 7/26/01 ir/jl