This is a servo arm for the 18th Scale OpenRC F1.
It fits on the 3,7g cheap ebay servos.
I used my soldering iron to quickly melt the inside of the hole and quickly pushed the servo arm onto the servo to get the teeth marks inside. After that mount the screw and you are good to go raceing.
A massive thanks to Daniel Norée aka Barspin for making the 1:10 scale F1.
And Nigel West aka NigelWest for making the 1:18 scale version that I'm able to print on my small printer. (exept for the bottom plate)