These are slip-over soft jaw covers for a Kurt-style machine vise. The STL fits my 8" knock-off perfectly. If you have a different vise, just fill in the jaw and block dimensions in the SCAD file and cut yourself a new STL.
This model is basically a box with a notch in it -- not anything that's going to stretch the capabilities of any printer. Use whatever settings you like. I like 5mm thickness and 5% infill to get some structural soundness while still ensuring these jaw covers will visibly fail before a workpiece they're holding would be marred up.