The Pro Plug Socket™ features an extremely thin wall design and easily slip into deep well engine heads to gain access to the spark plug. Spark plugs are well retained and easily removed via the unique retention system designed into the Pro Plug Socket™. When installing and removing spark plugs, the Pro Plug Socket™ can be driven in multiple ways, easily slip a 17 mm wrench over the top hex feature, use a rod via the through-hole, or use a ratchet with the 3/8” square drive.