"The EJ TGV Deletes were designed directly from OEM tumblers but with many enhancements. O-rings replace the metal gaskets on the bottom flange. We designed a slide block which allows movement or adjustment for the center manifold holes. This issue can be fixed by slotting the manifold holes out or a company offering multiple versions to accommodate different manifolds but our design fits all. The o-ring groove has been curved around an area on the manifold that has bolt head reliefs, this has been known to be a leak spot on other o-ringed TGVs. Lastly we have made it very easy to remove the o-rings.