These couplers work like the prototype. Mounting springs included. Contents 10 pieces. The standard 1 Gauge models produced since 1987 can have the regular claw coupler replaced with this reproduction prototype coupler. This coupler looks and works like its real life prototype. Running a train with this coupler usually requires a very wide minimum radius of 3.0 to 3.5 meters or 118 to 138, depending on the models. Current standard 1 Gauge models that can be retrofitted with this coupler can be identified by the symbol shown below.