This small board adapts the 9-pin Game port (Joystick port) on the Apple //c to accept 16-pin joysticks designed for the Apple II, II+ or IIe.
Based on suggestions from a user, I've created a second version of the adapter, with the 16-pin connection at a right angle to the IIc case. This accommodates joysticks and paddles with a molded connector instead of a ribbon cable. See the photos for more detail.
You can buy this item by itself, or as an add-on with the RetroConnector Joystick Interface.