Features Feature: The extractor can easily remove damaged screws, studs and bolts , spark plug Carbon Steel Material: The Screw Extractor Set removal tool is made of high hardness materials, and the standard size can help to easily remove the damaged screws, studs and bolts. 5 Sizes: We provide you with a 5-clock(No.1-No.5) screw extractor, which is sufficient to meet your various use occasions. It is specially used to remove damaged studs, bolts, socket head cap screws and accessories, which makes you more worry free. How to Use:You could use 12-pt. sockets to turn them with (Sock size depending on screw ectractor size). so you would need metric sockets to do that. Use a hammer to set them in the fastener first. Other possibilities are to use a tap handle from a tap-and-die set, or a small T-handle, Especially you Can use it remove the threaded part of a broken spark plug stuck inside the engine. Specification:Material: Carbon SteelColor: Shown as picture Packagelist:5 x Screw Extractors Package List