3/8″ Drive Spark plug 14, 16, 16 (thin wall) and 21mm. 1 x Spark plug socket 21mm. 3/8″ glow plugs 8, 10 and 12mm. 1 x Glow plug socket 12mm. 1 x Glow plug socket 8mm. 1 x Glow plug socket 10mm. Includes all the sockets and extensions required to remove/install spark plugs or glow plugs and oxygen sensors on most modern vehicles.