This is a set of optional ST Racing Concepts Pro-Racing CNC Machined Aluminum 1° Rear Toe-In Hub Carriers, and are intended for use with the Traxxas Slash, Stampede and Rustler. These rear hubs are designed to add 1° of outboard rear toe-in for increased stability and traction. CNC machined from high-quality aluminum material, these rear hub carriers hold tight-tolerances for an accurate 1° toe-in. A set-screw over the hinge-pin design secures the hinge-pin in the hub carriers. This design prevents wear from the hinge-pins on the hub carriers and also accurately holds the 1° toe-in angle. An additional camber link hole allows for a longer upper camber link rod for more stability and camber adjustments.Note: DO NOT use set-screw on stock hinge-pins. The set-screw hinge pin lock design is intended to be used with ST3640 Lock-nut style hinge-pins or E-clip type hinge-pins.