Set of 6 brown Viton and 6 black NBR O-rings, believed to suit various Porsche 996 applications including oil cooler, vacuum, and coolant seals. Came from a bulk lot of 996 service parts. 

Approximate measurements below:

Brown Viton O-Rings - ID: 30mm OD: 37mm
Black NBR O-Rings - ID: 25mm OD: 29mm