The AmazonBasics full-synthetic motor oil is a great choice because it is affordable and meets high standards. It has been approved by the API SN and ILSAC GF-5, meaning that it will help make your generator more efficient. It is available in different sizes to suit your needs and has a temperature range of 0 to 86°F. The oil can also help prevent build-up, meaning that the engine will be less likely to rust or corrode. In addition, the engine will run more smoothly.