A  caster wheel is a non-powered wheel assembly designed to be attached to the bottom of a larger object, enabling it to move easily.

This assembly typically includes the wheel & mounting mechanism, such as a fork or bracket, which allows for attachment to various equipment,machine or furniture.

Casters are commonly found on items like office chairs, shopping carts, hospital beds, and other material handling equipment like trolley,hand truck,plateform truck etc. They come in two primary types:

1. Swivel Casters: These have a wheel mounted to a fork that can rotate 360 degrees, allowing for movement in any direction. This design provides excellent maneuverability, making it ideal for applications where frequent changes in direction are necessary.

2. Rigid (or Fixed) Casters: These consist of a wheel mounted in a fixed frame, restricting movement to a straight line—forward and backward only. They are suitable for applications where directional movement is consistent and turning is not required.

The choice between swivel and rigid casters depends on the specific requirements of the application, including the need for maneuverability, load capacity, and the type of surface on which the casters will operate. 

If you want the equipment to stay somewhere,you can choose swivel caster with brake.