SF Shelf Whisker Coupler Medium (9/32") Centerset ShankThe 118 Kadee® Magne-Matic® Coupler features a Metal Coupler, insulated 242 Draft Gear Box and Lid with center screw holes for mounting. Shelfs actually work. The 118 Coupler may be mounted with supplied 242 draft gear box or with Manufacturers cast-on coupler pockets. Two pair per package Manual uncoupling requires the 241 Dual Tool. The "SF" Shelf Coupler can be easily modified to look like the type "F" Shelf Coupler or "H" Passenger Car Coupler. 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.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.Two pair per packagePackage Includes:(2) Pair SF Metal Shelf Whisker® Magne-Matic® Coupler - Medium Centerset Shank(2) Pair 242 Snap-Together Gearboxes(2) 622 Knuckle SpringsMounting Specifications:Mounting Height - 29/64"Centerline - 25/64"Trip Pin Height - 1/32"Center Hole - 2-56 Insulated Screws are the most commonly used. (Screw length will vary)