This is a direct servo horn made out of aluminum. It is designed to fit Tamiya and Futaba servos. Compared to a "servo saver" horn, which is spring loaded to absorb shock that can be transmitted to the servo gears, the direct horn allows users with highly tuned race cars to get optimum steering precision and direct feel.
This horn is only recommended for advanced users. It is mainly used on steering servos that feature metal gears and ball bearings. It is not recommended with servos with plastic gears.