You get two choices with Hitec's most popular servo the HS-81, resin or metal gears. A popular servo for smaller airplanes, heli's, boats, cars and trucks, the HS-81 offers a fine balance between speed and torque.
Specs:
Length: 1.17"
Width: 0.47"
Height: 1.16"
Weight: 0.58 ounces
Torque: 36.10 oz/in at 4.8V; 41.66 oz/in at 6V
Speed: 0.11sec/60deg at 4.8V with no load; 0.09sec/60deg at 6V with no load
Bearing Type: None, outer case serves as bearing
Gear Type: Nylon
Motor Type: 3 Pole Ferrite