An oval cylinder thumb lock is a type of lock that is typically used on doors. It has a cylinder shape with an oval-shaped thumb turn on the inside of the door, which allows the user to lock and unlock the door without using a key. The lock is designed to fit a standard hole size of 20mm, which is commonly found on residential and commercial doors. It is small in size, with a diameter of 54mm.

To use the lock, the user simply turns the thumb turn to lock or unlock the door. The lock can be opened from the outside using a key, which is inserted into the cylinder. The lock may also have a deadbolt function, which allows the user to lock the door in a more secure position by turning the thumb turn and extending the deadbolt into the door frame.

Overall, the oval cylinder thumb lock is a convenient and secure option for doors that do not require a high level of security. It is easy to install and operate and is suitable for use in a variety of residential and commercial settings.