Each bolt extractor is made of high hardness chrome-molybdenum steel for superior durability and longer life. It will easily extract damaged bolts, nuts, and screws even if they are stripped, rusted, or frozen. The internal thread with reverse spiral flutes design to bite down to provide maximum gripping power, the more you turn, the tighter the socket grips. Standard 1/2-inch drive to let the extractors compatible with common to heavy-duty power tools, drivers, and screwdriver handle tools. The steel bar for easier removal. 6 pieces 1/2 inch drive impact bolt & nut remover comes with 27mm, 22mm, 21mm, 3/4"(19mm), 17mm, and a steel bar. Heavy-duty blow-molded case lets all the bolt remover stay organized and take your set on the go.