Six piece stud, bolt, screw Extractor. Internal Screw type for removing right hand threaded studs, bolts large screws or threaded pipe. This type of Extractor is commonly used on bolts/studs that have snapped off flush preventing the use of external Extractors. Simply pilot drill the bolt/stud then screw in the correct size Extractor in an anti-clockwise direction. PLEASE NOTE: These Extractors are designed to be used on FREE (NOT Seized) Studs. Anybody lacking in experience of removing seized studs/bolts should get professional help from time served highly experienced exhaust fitters/motor technicians. Great care should be taken when using these extractors as incorrect use can cause damage to the tool or components! This is not to say they will not extract seized studs but great care and experience is needed to avoid any damage.