We have been using these for many years and have finally made them available to the public
These drop into a weld bung during assembly. The high heat transfer of aluminum and copper pulls heat from the threaded area of the bung during welding.
This helps immensely to prevent distortion of the threads.
Distorted threads are a common cause of bound up heim joints, if not addressed this can case sever damage to the heim joint and the bung, leading to expensive replacement .
These are available for common heim joint thread sizes.
Aluminum heat syncs are great for lower production runs, the aluminum doesn't transfer heat quite as well as copper, but the price point is significantly lower
The Copper heat sync is great for high production shops welding a large number of threaded bungs, copper is the ultimate heat sync and will last for many years.