This is a replacement slew hat and holder designed for a PS4/xbox style alps mini joystick (I bought generic ones off of amazon) for use with Deltaalphalima1's slew replacement board (https://forums.eagle.ru/showthread.php?t=200198). This allows users to swap the stock slew nub with a regular xbox style thumbstick (soldering skills required) and doesn't require any destructive modification of the throttle handle.