Omega D2 and zone VI cold light questions

[dhgustaf@gmail.com]

Hi all,

I picked up an Omega D2 with dichroic head from a local photo club. In addition to the D2 I was also given a box labeled Zone VI Cold Light. I'm trying to figure out what I have here and what I'm missing to set up and use the Zone VI head. I feel like I'm missing something that will let me attach the cold light to the enlarger. And what's that third plug on top of the cold light? Any help is appreciated.