EDIT: I just checked the Knipex website. Knipex manufactures a pair two models of pliers, both have slim jaws with a rounded toothed gripping surface similar to your pliers. While the pliers aren't a slip-joint design, one model does have an offset angled head like yours. Knipex calls them "Cycle Pliers," "for very narrow screw connections" The model is 84 21 200.