Mayhew Pro 66340 8.25 mm-12 mm 1/4-Inch Twist Socket Removes rounded or damaged fasteners with any head configuration (hex, round, square) One-quarter millimeter increments between sizes ensures coverage, regardless of fastener head condition or manufacturer's tolerance Manufactured from heat-treated alloy steel No hammering required to install socket over fastener; twist socket tightens as more torque is applied Additional applications include exhaust manifold nuts, studs, pipe nipples and corroded marine fasteners