Rim locks, also known as surface-mounted locks, are a type of locking mechanism that is mounted on the surface of a door rather than being mortised or recessed into the edge of the door.

Rim locks consist of a latch that is operated by a key or thumb turn on the outside of the door and a handle or knob on the inside. They are commonly used on wooden doors, particularly in older homes and buildings.

Rim locks can be used as the primary lock on a door, or as a secondary lock in combination with a deadbolt or other type of lock. They are available in a range of styles and finishes and can be either single or double-cylinder, depending on whether or not they can be unlocked from both sides.

Rim locks offer several benefits that make them a popular choice for securing doors.

Here are some of the advantages of rim locks:

1. Easy to install:  Rim locks can be installed on the surface of a door without the need for extensive modifications to the door or frame, making them a quick and easy option for securing a door.

2. Affordable:  Rim locks tend to be more affordable than other types of locks, making them a popular choice for homeowners on a budget.

3. Retrofittable:  Because they do not require mortising or recessing into the edge of the door, rim locks can be added to existing doors without the need for extensive modification or replacement.

4. Easy to operate: Rim locks can be operated from either side of the door using a key or thumb turn, making them a convenient and user-friendly option.

5. Versatile:  Rim locks are available in a range of styles and finishes, making it easy to find a lock that complements the style of your home or building.

Despite their advantages, it's important to note that rim locks may not provide the same level of security as other types of locks, and their exposed position on the surface of the door can make them more vulnerable to tampering or forced entry.

It's always a good idea to consider the specific security needs of your home or building when choosing a locking mechanism.