If you're looking at this listing, you probably have a DOS Compatibility card in your Mac, but lack the adapter to use the darn thing. This was my situation as well, so I decided to create my own solution. This custom assembly is a direct replacement for the bulky and ultra-rare "Y-Cable". Each assembly is fully tested in my Power Macintosh 6100 using a period-correct Apple CRT monitor. It is also compatible with the Quadra 610. This adapter allows the use of a dedicated monitor with your DOS card, or monitor sharing between the Mac and DOS environments. Additionally, the joystick port allows controllers to be connected on the DOS side. What you see is what you'll receive (HD26 cable, adapter board, and 3D printed case). Thanks for looking and have a great day!