High quality stud extractors suitable for the professional and the enthusiast alike. Concentric roller bearing type removes studs without damage to the threads. Manufactured from chrome vanadium steel with a polished finish. Can be used to remove or install studs. Suitable for use on metric or imperial studs. Will not damage thread. Normally used with a ratchet but if you have a long stud then you can let the stud pass through the extractor and use a spanner. The 6mm and 8mm extractors are a 19mm spanner and the 10mm and 12mm extractors are a 22mm spanner. Supplied in a blow molded case for storage and transportation. Includes; 6mm (1/4") stud extractor (3/8" drive and total length 30mm) 8MM stud extractor (3/8" drive and total length 30mm) 10MM (3/8") stud extractor (1/2" drive and total length 37mm) 12MM (1/2") stud extractor (1/2" drive and total length 37mm)