This is a set of 10 pieces sturdy tools to help remove damaged nuts, bolts, screw heads, studs, etc. Features: Spiral cut t-eeth provides a positive grip to remove rounded or damaged bolts. The damaged nut bolt extractor is made of hard alloy, they are of strong strength and long durability. Can also be used on screw heads and studs. Will fit heads sized 9, 10, 11, 12, 13, 14, 15, 16, 17 and 19mm. Can be driven with a metric spanner or socket. Specifications: Type: high cased, low cased (optional) Material: alloy Color: black Package size: 100 * 100 * 50mm / 3.9 * 3.9 * 2.0in Package weight: high cased: 474g / 1.0lb low cased: 230g / 8.1ounce Packing List: 1 * Screw Remover Tool Kit