The kind that will get the job done...user/abuser. Looks like its missing a pipe jaw, can't see that well. Sorta looks like Allied, but I think those are usually marked as such.
Do you know which model was pre-tension knob on the spring? I'm asking since I just picked up an older Atlas 15" DP and can't find any model info...reading through a couple of posts trying to figure it out. I thought it was #64 but as stated it doesn't have a knob to release the tension on...