For cleaning / rubbing out the glow plug hole Cleaning is recommended before inserting the new glow plug Suitable for a variety of engines from Audi, Alfa Romeo, BMW, Fiat, Nissan, Opel, Peugeot, Renault, Toyota, etc. Includes 4 reamers in the following sizes: M10 x 1.00, length 107 mm, M10 x 1.25, length 137 mm, M12 x 1.25, length 59 mm, M12 x 1.25, length 94 mm Material: chrome molybdenum, titanium coated