The invention relates to pliers for changing the distance of two activation surfaces of a connection or fitting for conduits. The change of the distance correlates with an elastic or plastic deformation of at least one component of the fitting including a radial crimping process. The inventive pliers comprise two hand levers linked by a transfer mechanism with two spreading jaws. According to the invention, a closing movement of the hand levers results in a spreading movement of the spreading jaws. Such spreading movement of the spreading jaws is used for plastically deforming at least one of the components of the connection by a radial crimping process.