This cylinder head gasket is for engines, Dirt bike 150cc (engine number starting with 1P56).
The gasket cylinder head is that it seals between the cylinder and the cylinder head, and must important against thermal stress, mechanical and chemical resistance.
The first symptom that you can determine if there is a problem with the cylinder head gasket is the most important, white smoke escapes the exhaust. It is accompanied very quickly to an overheating of the motor. This can lead to suffocation, that the sealing is no longer guaranteed.