Made of chrome vanadium steel, high hardness, rustproof, strong and durable The drill bit diameters and recommended extraction diameters of broken screws are engraved on the case The extractors and drill bits with great gripping force Ideal for removing damaged, rusted or stripped screws, studs, bolts, fastener, metal water tap and water tube, etc. The drill bits can also be used for drilling holes on wood, metal, plastic, brick and wall, etc. Product Description SPECIFICATION: Extractor Diameter: #1 for 1/8"-1/4" (3-6mm) #2 for 1/4"-5/16"(6-8mm) #3 for 5/16"-7/16"(8-11mm) #4 for 7/16"-9/16"(11-14mm) #5 for 9/16"-3/4"(14-18mm) Drill Diameter: #1: 5/64" (2.0mm) #2: 7/64" (3.0mm) #3: 5/32" (4.0mm) #4: 1/4" (6.5mm) #5: 19/64" (7.5mm) Package Includes: 5 x Drill Bits 5 x Extractor 1 x Faucet Fixing 1 x Storage Box