The #23 Kadee Magne-Matic Coupler features a very strong plastic isolated coupler, #634 Centering Spring, (same gear box as the NO.5 Coupler), insulated #234 Draft Gear Box and Lid with side and center screw holes for mounting and the (20-Series draft gear box) insulated #213 Universal Adaptor Plate. UPC: 765484000235