This is an optional Exotek Aluminum HD Servo Horn in Black color, designed to match the dimensions of Team Associated 1/10 scale vehicles. This horn can also be used with other vehicles where applicable.
This horn is made from 7075 aluminum alloy to prove the strength needed with high torque servos, and the rigidity plastic horns cannot compete with. To secure the brilliantly polished and anodized horn, a M2.5 screw clamps the horn to the spline.
Note: there is also a blue version.
Great work as usual from Exotek.