Ozone and Sunlight Sterling Seal ORSIL318x1000 Number-318 Standard Silicone O-Ring has Excellent Resistance to Oxygen 1-7//16 OD 1-1//16 ID Pack of 1000 Vinyl Methyl Silicone Pack of 1000 Sur-Seal Inc. 1-1//16 ID 1-7//16 OD