These are very high quality valve cover gaskets (for both valve covers) with the spark plug well seals. Replace your hard valve cover seals before they leak a bunch of oil on to your exhaust, causing an unpleasant smell or even a fire. Leaking spark plug well gaskets can also cause misfires over time as oil gets past the spark plugs.
We have used these for many, many years without issue and find them equivalent to the stock original Mitsubishi ones.