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 preventing fasteners from rounding. Supplied on a metal socket rail. • 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: 1/4″Sq Drive; 3-6mm, 3/8″Sq Drive; 7-10mm.• Supplied on a metal socket rail.• Lifetime guarantee*.