Grip more of your fastener head with these wrench heads. They have a hex or 12-point opening with more surface area than rounded wrench heads, so they make more contact with fasteners for a better hold. Also known as flare-nut crowfoot wrenches or line wrenches, they're often used with flared tube fittings as well as fuel and hydraulic lines. Connect them to a socket extension and ratchet wrench to turn fasteners where clearance is limited from both the top and side. You can also attach one directly to your ratchet wrench to convert it into an open-ended ratcheting wrench.