1. The package includes 13 pieces of multi-spline screw extractors. And the size is 1/8Inch, 5/32Inch, 3/16Inch, 7/32Inch, 1/4Inch, 9/32Inch, 5/16Inch,11/32Inch, 3/8Inch, 13/32Inch, 7/16Inch, 15/32Inch, 1/2Inch 2. [Main Function] This screw extractor kit is used for removing broken studs/pipes and screws. This kit can help you efficiently remove the toughest broken fasteners. 3. [Alloy Steel Material] This screw extractor is made of premium alloy steel material, which has high hardness, rust-proof, reliable and durable to use. 4. [Left-Handed Helical Design] Our screw extractor adopts powerful multi-tooth and a left-handed helical design for extra holding power and faster threading speeds. Helical grooves insert into itself to increase grip and reduce drag. Please note:There is a slight color difference or difference in kind, it does not affect the use, please do not mind, thank you! Colour:Black Material:steel Package Contents: 13 * Screw Extractor Kit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.