Park Tool MWF-3 Metric Flare Wrench. A purpose-built wrench designed for compression nuts nipples and other fittings found on hydraulic brake systems. The five-sided flare wrench head evenly spreads out the force being applied to the wrench reducing the risk of damage to fasteners and brake hoses. Features a slim low-profile design to access low-clearance fittings found on hydraulic levers and calipers. Built-in 3/8″ fittings allow for use with a torque wrench to achieve proper torque.