This is the upmarket version of the Flight Control System Mark I joystick with a rubber boot to keep dust out. It's a scaled down replica of the F-4 Phantom joystick.
The FCS Mk II also featured b7etter quality switches and much stiffer springs.
Why the stiff springs? I found my copy of the original manual and dig out this interesting information: Stiff Springs in joysticks.
Image used with permission from Jan-Albert van Ree