Connect a Super Nintendo SNES gamepad to your C64.
Features autofire and joystick port switching VIA the gamepad itself. Also you can customise the button configuration using the configuration PRG file which can be found on the developers Github page.
The adapter connects to both C64 joystick ports and allows the active port to be changed on the fly with a push of a button. The interface defaults to joystick port two on power on.
Also, the interface allows up to four custom mappings to be programmed using a C64-side application. The custom mappings allow any combination of joystick port two and port one control lines to be mapped to any of the Super Nintendo controller action buttons (A,B,X,Y,L,R). Any of the action buttons can also have an optional rapid-fire function applied, of which a normal and 'inverted' state is available. 'Inverted' rapid fire is simply that when active the output state of the effected button will be opposite to of a normal rapid fire button when pushed. For example, mapping a button to joystick left with rapid fire and another button to joystick right with inverted rapid fire will simulate a rapid left/right joystick waggle when both buttons are pushed.
More information can be found here