Either a q85 or q100 from the looks of it. Almost the same motor but the q85 are suited for the slimmer forks typically found in folding bikes. The q100 are suitable for the standard 100mm fork widths. Just from the picture, I couldn't say if it's a q85 or q100. The controller looks to be a KU63 as well.
I got my q85 from BMSbattery.com so if you want specs for that motor (and the q100) go to that site.
Edit:
click this for the link to the various q85-q128 kits here
Looking at this site now has me hessitating what motor/controller combo it is without actually proof of motor model # from your picture your showing us...
I'd ask the person auctioning the item for more info on the motor. What really isn't shown in the picture is what RPM wind it is. I'd think that's important info.