This is a pre-owned Rear Bumper/Diffuser Panel from a 2007 Lotus Elise. This should fit on most S2 generation Elise models, with this one being specifically from a US-spec 111R with the 2ZZ engine. This panel is to be fitted between the rear clamshell and the diffuser of the car, and it is designed for a license plate to be screwed into it. 

The OEM part number is A121B0139F. 

As seen in the pictures, it should be noted that this product is missing some studs and rivets. The fiberglass heat shielding is tattered, as well. These flaws have been taken into account, as the pricing is set to approximately 25 percent of the current MSRP.