B&M Racing & Performance brings you this billet aluminum speedometer port block-off plug that fits all Tremec 3550, T-5, TKO 5-speeds, Magnum 6-speeds, Borg Warner T-45 manual transmissions and Ford C4, C6 AOD, 4R70W & 4R75W automatic transmissions. The plug is used to block the mechanical speedometer gear port when upgrading to an electronic speedometer and includes a replaceable silicone rubber o-ring to keep oil from leaking out, and contaminants from getting in your transmission. It features a black Mil-Spec anodized finish for long lasting good looks, even in harsh conditions. Comes with installation instructions for an easy and quick installation.