Bracket for Continental Flex Fuel sensor. The sensor clips into the bracket as GM had originally intended. There are two M6 sized mounting holes which are spaced 55mm apart. 

I have it setup to print vertical with supports to ensure the layers are the correct orientation to reduce the chance of the locking tab from breaking off. 

This will work with many other popular aftermarket flex fuel sensors such as Haltech or AEM as they all use the same Continental sensor.