Wilton 4" bench vise  softjaws (print 2), magnet pocket for 1.5"x.25"x.25" bar magnet, but i made it deep enough that you can hot glue in whatever strong magnets you might have laying around.

I printed mid with 6 wall layers and a 40% cubic subdivision infill. It might not be a bad Idea to print yours solid if you are using them for heavier clamping loads.