www.safetyandhealthmagazine.com/articles/anti-rolling-casters-2

Anti-rolling casters

January 1, 2012
Anti-rolling casters help reduce falls by preventing stools from rolling away when users stand up or sit down. A caster locks the wheels when weight is removed, but allows rolling movement when someone sits on the seat. The casters are easily retrofitted to standard stools and ideal for workers in the health care or science fields.

AliMed Inc.