GM Genuine Parts A/C Line O-Rings are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These O-rings are used for forming a gas-tight connection between air conditioning components. The A/C O-Rings should be lubricated with Viscosity 525 mineral oil to prevent leaks and fitting corrosion. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).