This one.

Note the connector on the expansion box chassis. It connects to that.



For the avid rebranded and the ProTools audio interface boxes, both have connectors that look like HD50. All that I got that is the same are these and I got a fair number of them. Would they suffice for the job?

The SIT card is undoubtedly the mac version of the Mach64. I ued to have one in my first pentium box. They were quite nice and yes, those appear to eb SIMM doublers. I didn't even know that was possible.