Cylinder Liners Sleeves, made of grey cast-iron, ought to have desired casting and machining qualities, viz. strength, toughness, hardness and wear resistance. These are mainly of two types Dry liner-sleeves and Wet liner-sleeves.

It is in direct contact with engine block. The outer diameter is very precise and perfect without contours.

It comes with sealing grooves for 'O' rings and is always in direct contact with water. A wet liner is generally heavy and thick walled.