Bolt hole castor made from pressed steel fitted with a thermoplastic polyurethane wheel which also has roller bearings which greatly improve rolling resistance . These bolt hole casters range from 100mm-125mm and have a capacity up to 260 Kg per caster. polyurethane sometime known as poly nylon wheels and castors offer high load capacity compared to many wheel materials. They are light in weight and very hard wearing and good value for money. They help reduce the likelihood of floor damage which which can happen. We would recommend polyurethane tyred castors and wheels when cost is a concern and a smooth floor is likely, By using a polyurethane tyred wheel you reduce the likelihood of floor damaged which is often to the case when using stand white nylon or Polypropylene as a wheel material. Whilst Polypropylene or Nylon wheel work well and offer a very cost effective solution they often cause floor damage which can be costly to repair.