Yeah Racing Traxxas TRX-4 2.2kg Micro Metal Geared Servo. This optional servo is great for switching gears and locking differentials in the Traxxas TRX-4/TRX-6. This also makes for a great upgrade to the Traxxas TRX-4M steering servo! With full metal gears, this servo has the durability and reliability to get out on the trail. Being waterproof means you can take this servo anywhere the trail might lead you. Two servo horn styles are included to allow this servo to be used in many applications. Package includes two servo horns, one servo and hardware.