Quickly Replace your Apple /// Power Supply with a modern solution! Works with the Apple /// and Apple // Plus. Mounts to your power supply base plate using your original Power Supply screws.

This is the Core Unit, which includes a main ATX-to-A3 Adapter breakout and 3D Printed Mount.

You probably want to check out the Build A Kit page, where you can select all the things you need to make a full A3 ATX supply for your needs!