Abstract: An apparatus for protecting the open end of the female half of a metallic hydraulic line coupler when the female half is not coupled to the male half of the coupler is provided. The apparatus includes a magnetic cover member releasably attachable to the female half of the coupler by the exertion of magnetic force thereon. The cover member has a first surface which completely covers the open end of the female half of the coupler when the cover member is magnetically attached thereto. Magnetic force deflecting means are attached to the magnetic cover member for redirecting at least a substantial portion of any of the magnetic force directed away from the female half of the coupler toward the female half of the coupler.