GM Genuine Parts Vapor Canisters are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These canisters capture and store evaporating fuel vapors from the fuel tank to be drawn into the intake manifold during engine operation. 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).