The rubber fitting on the bottom of the plenum that is bolted to the "P" clip connecting it to the engine frame. Disconnecting and re-connecting this is the most difficult part of the operation. Didn't take an overall pic of the completed install. Will do that Wednesday evening when I'm back in the shop cleaning up in preparation for spraying the last three coats of primer on the fuselage. Also plan to complete priming of the doors, control surfaces and speed kit pieces at that same time.