These new AFX pickup shoes are made in the USA from phosphorous bronze. They are an exact copy of the original Aurora long step AFX and Magna-Traction pickup shoe. These shoes underwent a stringent Quality Assurance examination, where 26 different locations were measured and compared to the original Aurora shoes. Many original Aurora AFX and Magna-Traction chassis used phosphorous bronze for the chassis but some did use other materials including (what appears to be) nickel silver or silver plating over phosphorous bronze. Phosphorous bronze has excellent electrical conductivity and low resistance, with the added benefit of being less costly.
Original Johnny Lightning and Auto World chassis appear to use nickel silver for their pickup shoes. Replacing the shoes with those made from phosphorous bronze will not result in any loss of performance. Just be aware the color of bronze is different than nickel silver.
These pickup shoes will work for all Aurora AFX and Magna-Traction, as well as all X-Traction chassis.