This is a Dual End Ball Link from Great Planes.
This simplifies a dual aileron setup.
FEATURES: Ideal for pilots who are flying with just one aileron servo
Costs less than a two-servo system, and requires less setup
Can also be used for rudder/nose gear linkage
INCLUDES: One 2-56 Threaded Ball (ball=3.85mm) with tightening nut flange
One Nylon Ball Cup (socket) (not prethreaded)
Two 2-56 Threaded Couplers (Solder Linkage Rods)
One Nut goes under servo are on threaded ball
One Washer goes under servo arm on threaded ball
REQUIRES: Solder, Soldering Iron, 2-56 Pushrods