This product is designed to be used with a socket wrench to unscrew oil filters that have become stuck to their mounting faces, usually as a result of being fitted 'dry', i.e. with no smear of oil applied to their rubber gasket. It is often impossible to remove such filters without first puncturing them right through with a heavy gauge screwdriver and then using the screwdriver as a lever to rotate the filter body. These specially designed oil filter removal tools come in various diameters and numbers of flutes and the best way of determining the required dimension is to buy a new identical filter, measure the diameter with calipers and count the number of flutes around the perimeter of the filter canister. Using these products will prevent most of the inevitable oil spillage resulting from other 'agricultural' solutions.