Optional M4 Upper Arm Adjuster Screw for RC MAKER SP1 and SP1-F
This screw connects the upper arm and upper arm ball cup together and allows the adjustment of camber.
These were an update to the last batch of kits and feature an additional drilled hole from the other side of the screw to lighten it. You can identify them by them having a hex in one end, and a hole in the other.