The first being durability
Motor Limit: 2S LiPo or 6 cell NiMH: 540 or 550-size motor great than or equal to 12 turn
Universal driveshafts offer more efficient transfer of power to the wheels
Titanium gray anodized shock bodies and caps
Molded nylon 3D wing and mounts
HPI Racing - HPI SSL-12MGWP Servo, Waterproof, 7.4V, 35Kg, Metal Geared GMA52012 The first being durabilityThis waterproof, digital,large scale metal gear servo is ideal for bashers and racers looking for a tough and durable servo for absolutely any kind of condition. Use this in your Baja buggy or truck, or any kit that requires a large scale servo. Features: Operating Voltage: 6 7. 4V 6V: Speed: 0. 18 sec 60 degrees, Torque: 28kg cm 7. 4V: Speed: 0. 15 sec 60 degrees, Torque: 35kg cm Servo Spline: 25T Specifications: Main case: 65. 8x59. 1x30. 0mm