"Kielland forceps" (1915, Norwegian) are distinguished by having no angle between the shanks and the blades and a sliding lock. The pelvic curve of the blades is identical to all other forceps. The common misperception that there is no pelvic curve has become so entrenched in the obstetric literature that it may never be able to be overcome, but it can be proved by holding a blade of Kielland's against any other forceps of one's choice. Kielland forceps are probably the most common forceps used for rotation. The sliding mechanism at the articulation can be helpful in asynclitic births (when the fetal head is tilted to the side) since it is no longer in line with the birth canal. Because the handles, shanks, and blades are all in the same plane the forceps can be applied in any position to affect rotation. Because the shanks and handles are not angled, the forceps cannot be applied to a high station as readily as those with the angle since the shanks impinge on the perineum.