A doorstop is a device used to prevent a door from closing or to keep it permanently open. There are several types of doorstops, each with a slightly different working principle:

Wedge-shaped doorstop: This type of doorstop has a simple structure, usually made of rubber or wood, and is wedge-shaped. It’s easy to use; simply place it under the door. The wedge design increases friction between the door and the ground, preventing the door from moving.

Spring-loaded doorstops: These doorstops are typically installed on a wall or floor. When the door swings open outwards, it hits the spring-loaded doorstop, which absorbs the impact and prevents the door from hitting the wall. Some spring-loaded doorstops can also be pressed down to keep the door open.

Magnetic doorstop: This type of doorstop consists of a magnet attached to the wall and a metal plate on the door. When the door is opened, the magnet attracts it, preventing the door from closing automatically.

Kick-type doorstop: This type of doorstop is installed at the bottom of the door and can be activated by kicking the control lever downwards. Once activated, the doorstop creates friction with the ground, thus securing the door in place.

Floor-mounted doorstops: These doorstops are installed directly on the floor and can be simple rubber or metal protrusions. When the door is opened, it hits these protrusions, thus preventing the door from moving further.

While all doorstops serve the same basic purpose, their design applications and target audiences differ. They can protect walls and furniture from damage caused by swing doors, and in some cases, they can enhance security by keeping the door open.