Urethane Braking Casters - Hard Floor. These safety casters prevent chairs from rolling freely when unoccupied, then release to roll freely when weight is added. These safety braking casters prevent chairs from rolling freely when unoccupied, then release to roll freely when weight is added. This safety braking feature has long been required on production seating sold in Europe. Hard surfaces like concrete and tile will wear down the wheels on standard casters.