The Hybrid Racing PRB to ZDX throttle body adapter allows you to bolt a throttle body from an Acura ZDX engine onto an intake manifold with a "PRB" style flange. The popular large plenum Skunk2 street intake manifolds are great for power but have a drive-by-cable bolt pattern, making them difficult to use on a newer generation platform. This adapter allows users to bolt on the largest OEM drive-by-wire throttle body onto one of those intake manifolds without any modifications. This is a suitable part for the 06-11 Civic Si or 12-15 Civic Si using the larger Skunk2 style street intake manifold. The kit has everything you need to install in less than 30 minutes. The adapter has an inner diameter of 74mm.