PENNINGTON BLACKHAWK JIG The Blackhawk 303 sharpening tool was the first of its kind to be produced using a square steel centre tube to hold the alignment between the ends. The extra feature of the five point of contact design in the Blackhawk 303, allows the blade to be adjusted within one thousandth of an inch for unsurpassed blade control. High strength, high impact aluminium extrusion. The Blackhawk 303 is possibly the most durable and the most accurate on the world market. Alloy ends attached to square steel centre tube eliminates twists even on uneven surfaces. The Blackhawk features adjustable stops in the arms that allow you the option of two or four point contact with the skate blade. The Blackhawk also offers blade height adjustment, adjustable rear end stops that maintains an exact sharpening position every time.