Saitek USA
Makers of Saitek X-52 joysticks and other game/software controllers.

Logitech
Makers of Logitech joysticks and other game/software controllers.

CH Products
Makers of CH Gear such as flight simulation pedals, joysticks, and throttle controllers.

FlightLink
Makers of FlightLink helicopter simulation cockpit controls.

Helicoptersim.com
Makers of the Ryan Helicopter Simulator controller package.

RC Simulations
Makers of the Copycat Helicopter Simulation Controller package.