Specifications: This is a set of 10 pieces sturdy tools to help remove nuts, bolts, screw heads, studs, etc. It fits heads sized 9, 10, 11, 12, 13, 14, 15, 16, 17 and 19mm. Spiral cut teeth provide a positive grip to remove rounded or damaged bolts. Made of hard alloy, they are of strong strength and long durability. Instructions: First, choose a broken wire extractor that is thinner than the broken screw, and then find a drill bit the same size as the thinnest end of the broken wire extractor, and drill a deep enough hole in the middle of the broken screw. Then screw the broken screw counterclockwise with the broken wire extractor until the broken screw is unscrewed. Item Name: Nut Remover Tool Quantity: 11Pcs/Set Material: Chromed Vanadium Steel Adapter Head Size: 9mm/0.35", 10mm/0.39", 11mm/0.43", 12mm/0.47", 13mm/0.51", 14mm/0.55", 15mm/0.59", 16mm/0.63", 17mm/0.67", 19mm/0.74" (Approx.) Features: Durable, Easy to Use, High Strength High Type Box Size: 17.5cm x 8cm x 4.5cm/6.89" x 3.15" x 1.77" (Approx.) Short Type Box Size: 16.5cm x 10.5cm x 5.1cm/6.5" x 4.13" x 2" (Approx.) Notes: Due to the light and screen setting difference, the items color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 10 x Nut Remover Tool 1 x Black Rod