These custom twin wheel casters are offered with several options. Your choice of Chrome or Black hoods. The dual wheels have a larger 2.4" diameter for smooth rolling. Twinstar is weight rated at 100 lbs per wheel for strength and performance. These chair wheels offer your choice of stem options to fit almost any chair. Click here to view stem options. Please specify the stem option accurately. You can also specify either hard or soft treads. Soft treads are designed for hard floor surfaces like hardwood, linoleum, tile, parquet, concrete, chair mats, low pile carpet, etc. Hard treads are suitable for most kinds of carpet. Easy installation, just pull out the old chair wheels and insert the new ones. This product is offered in your choice of 4 or 5 pieces per set, specify your choice below. Specify a quantity (Qty) of 1 for 1 set.. 2 for 2 sets.. etc. Satisfaction guaranteed, if product does not meet your needs, just return within 30 days for a refund (shipping is not refundable). If you have any questions, please call toll free.