These caster wheels are ideal for furniture and office chairs which will rest on hard floor surfaces like hardwood,ceramic tile,marble,cement,and extra thick plastic mats. The body is made of nylon with a hood to help conceal trapped dirt. Twin wheel design enhances weight distribution (maximum 100 lb per wheel unit) and smooth operation. Swivel and roll freely and quietly in every direction with no need for maintenance. Material:Plastic,Metal Connector360 Degree Swivel Rotation,fits all office chair baseFits all office chair basesSwivel and roll freely and quietly in every directionIdeal for furniture and office chairsThese caster wheels are ideal for furniture and office chairs which will rest on hard floor surfaces like hardwood,ceramic tile,marble,cement,and extra thick plastic mats. The body is made of nylon with a hood to help conceal trapped dirt. Twin wheel design enhances weight distribution (maximum 100 lb per wheel unit) and smooth operation. Swivel and roll freely and quietly in every direction with no need for maintenance. Material:Plastic,Metal Connector360 Degree Swivel Rotation,fits all office chair baseFits all office chair basesSwivel and roll freely and quietly in every directionIdeal for furniture and office chairs