t is 7/8" inside diameter. Replaces Part# 079084-01. It is about 1" in diameter Oil Tank Cap/Bulb ASM 079084-01 fits Remington MTD Craftsman Pole Saw ChainsawPart Number :631-04381 107512-01, 079084-01The oil cover of the chainsaw is an important part in the maintenance of the chainsaw. It is located in the engine part of the chainsaw and is responsible for sealing and protecting the oilThe main function of the oil cover is to prevent the oil from spilling when the chainsaw is running, while keeping the oil clean and stable. It can also prevent dust and impurities from entering and protect the mechanical parts inside the engine from damageIn order to ensure the normal operation of chainsaw and prolong its service life, it is very important to check and maintain the oil cover regularly. When checking the oil cover, pay attention to whether it is damaged, deformed or leaking oil. If these problems are found, replace the oil cover in timeAlthough the oil cover of chainsaw is a small part, it plays an indispensable role in the maintenance of chainsaw