These are the extended headlight cap for 2014+ Silverado 1500 to clear the FXR projector upgrade. You will need two to do both headlights your truck. It was made with as large of a initial cavity with hopes it would also help with people wanting to install LED lights into the stock projector and I have just got confirmation they work with the VLED lights. He said they were a little tight on the wire, but cleared and ordered one for the other side. He is also using them to replace the bottom caps which I had never even thought about testing.
This thin model was made to reduce the price by taking extra material out of the base or seal area. Didn't know it cost more for the material when first mading these. The tower part is the same thickness as the original.