Soft edge brake loaded chair castors compatible with all of our chairs.  A combination of Brake Loaded and Soft Castors. 
 
This type of castor allows the chair to be freely moved around as with standard castors, when no one is sitting on the chair.  When there is weight on the chair, a brake is applied to the castor wheels and prevents the chair from moving.  This helps with safety to prevent the chair from sliding forwards or backwards if the 'user' leans to far one way or the other, but allows the chair to be moved easily when no one is seated.  With a hard rubber edge on the wheels to help with grip and help the castors to roll rather than slide on hard floors such as tiles or laminate floors.
 
Castors simply push into the chair base and removed by pulling straight out.
 
Sold as a set of 5 castors.