If you are looking to upgrade your Rush Evo differential then these new Gear Diff Bevel Gears (13T and 10T) are the perfect option parts for you! Made from steel, these bevel gears replace the standard alloy bevel gears (A850) and provide extra strength and durability for both on and off road driving - helping to preserve the integrity of the differentials. All new Rush Evo's now include these steel bevel gears as standard within the kit. All existing Rush Evo kits that contain the alloy bevel gears (A850) can be easily upgraded using these steel bevel gears. These steel bevel gears are also compatible with many other HPI kits.