Ruf Bumper, it is for an SC/Carrera flared 911..
Ruf Rear Bumper...... - Rennlist Discussion Forums
$2K
Not my eBay ad, just for reference
Porsche 930 Turbo Original Genuine Carbon Fiber Ruf Rear Bumper | eBay
And you can see the whole brochure here:
RUF Brochure