This tool's slip-joint mechanism engages with 11 stops over a 2" range, letting you adjust the jaw opening for a close fit with the fastener. With just a firm push on one handle, the jaws quickly slide closed; if additional fine tuning is needed, the push-button jaw release fully disengages the stops to permit careful positioning. The hardened, asymmetrically notched jaws capture three sides and two corners of a fastener for a secure hold with less risk of rounding the corners.