This is a set of 10 heavy duty tool heads to help remove nuts, bolts, screws, nails etc It fits head sizes 9, 10, 11, 12, 13, 14, 15, 16, 17 and 19mm Spiral cut teeth provide a positive grip for removing rounded or damaged bolts Made of alloy tough, they are of high strength and long life. These tools can be ordered with a socket wrench measurement or for quick work Features: This is a set of 10 heavy duty tool heads to help remove nuts, bolts, screws, nails etc. It fits head sizes 9, 10, 11, 12, 13, 14, 15, 16, 17 and 19mm. Spiral cut teeth provide a positive grip for removing rounded or damaged bolts. Made of hard alloy, they are of strong strength and long service life. These tools can be ordered with a socket wrench measurement or for quick work. All of these tools are packed in a case for easy storage and carrying. Specifications: Material: Alloy Color: Black Fit head size: 9mm/0.9cm, 10mm/1cm, 11mm/1.1cm, 12mm/0.47, 13mm/1.3cm, 14mm/1.4cm, 15mm/1, 5cm, 16mm/1.6cm, 17mm/1.7cm,