• One of a comprehensive range of Premier Hand Tools, suitable for daily professional use. • Professional heat treated Chrome Vanadium steel sockets. • S2 Steel hex bits with a zinc phosphate finish. • Removes rusted, damaged and severely rounded hex head fasteners with ease. • Patented twist design grips tighter as they turn. • Prevents fasteners from rounding. • Sizes: 3, 4, 5, 6, 7, 8, 9, 10mm. • Supplied on a metal socket rail. • Lifetime guarantee*.