Rollerblade Style Casters 
These are to fit Herman Miller and a variety of other brands of office chairs
The outer ring of the caster is made of strong and non-deformable PU material. The caster core is made of high-strength materials, so the caster can bear a weight of up to 120kg. 
[Noise-free performance] The ball casters slide freely on the floor, no noise, comfortable, quiet
Wheel Diameter 75 mm (standard caster is 60 mm), ideal for ensuring cylinder end clears carpet.
 
Please note, when ordering with a chair for international delivery, a separate delivery charge is added for the casters. Please contact us prior to purchase and we can invoice with the additional shipping charge deducted