Swivel stem caster wheels, sturdy and durable, polyurethane wheel, absorb shock, shock absorption, non-slip wear, suitable for most floors, do not worry about scratching your expensive wooden floors; | Precise ball bearings, rolling smooth and quiet, bid farewell to harsh noise; strong bearing capacity, lockable ball bearing 330lbs; | Swivel stem casters with brake locks, braking both plate and wheels, when put into the brake, the construction stops rotating or rolling; | Replacement for office chair stem caster wheels, suitable for furniture, electric appliance, flight boxes, tool boxes, trolleys, etc.; | Wheel size: diameter * thickness: 50mm*24mm(1.97*0.94inch). Stem size: M8-1.25×25mm. Each set contains 4 wheels with brakes, 1 wrench.