This website has 2 options. There is a Gtx 1080 and a Gtx 1080 sli. I was wondering if I could get the Gtx 1080 version and add a second Gtx 1080 later.
https://m.newegg.com/product/index?itemnumber=9SIABFS5AX9490
https://m.newegg.com/product/index?itemnumber=9SIABFS5AX9490