Polyurethane wheels-the protective wheel that wears like steel-is Hamilton's highest quality urethane, liquid cast to a thickness of approximately 1/2" and chemically bonded onto heavy-duty iron wheel
centers. The distinctive green treads are chemically inert, non-sparking, non-conductive, impervious to oil, ozone, grease and most solvents, and will not mark floors. Polyurethane wheels are also guaranteed against tread separation for one year in ordinary free-wheeling applications (contact factory for excepted applications). They are available without bearings, with straight roller bearings, or with precision tapered bearings as listed below. All sizes except the 3 " and 4" diameter include ball-check lubrication fittings in the hub.