A professional quality set of extractors to remove broken studs, pipes, set screws, grease fittings, etc. Manufactured by US.PRO Tools (formerly known as Bergen Tools), one of the more respected hand tool manufacturers on the market. Featuring large, serrated, reverse thread with a channel that aids engagement with the work piece. Manufactured from CR-MO (Chromium Molybdenum Steel) with heat treatment to obtain maximum hardness and a phosphate black finish. Contains the following: #1 – 3mm for extracting fixings 3mm to 5mm in diameter. #2 – 4mm for extracting fixings 4mm to 6mm in diameter. #3 – 5mm for extracting fixings 5mm to 8mm in diameter. #4 – 6mm for extracting fixings 6mm to 9mm in diameter. #5 – 8mm for extracting fixings 8mm to 11mm in diameter. #6 – 10mm for extracting fixings 10mm to 13mm in diameter.