This is a genuine cylinder head bolt replacement designed for use on select small engines found in outdoor power equipment. The cylinder head bolt is responsible for securing the cylinder head in the engine. It is exposed to constant vibrations and high pressure, which can lead to eventual wear and damage. These bolts will need to be replaced immediately if they become damaged or broken. If the bolts are not replaced, the cylinder head will not be secure and that could cause further engine damage or total failure. This genuine OEM replacement bolt is manufactured by Tecumseh and designed for use in engines in a number of its small outdoor power machines. This part is compatible with dozens of engines and the exact number of bolts and placement may vary based on the model. The parts diagram should provide information on the application and location of this part. This bolt is sold as an individual unit, and those who need more than one will have to order multiple quantities. Always wear gloves for hand protection and allow the engine to cool before performing any engine repairs. This replacement bolt requires a hex socket or screwdriver.