This is a used set of four heavy-duty swivel casters suitable for a large amp/speaker cabinet or road case. They are metal framed casters with 2-3/4" diameter and 1-5/8" wide non-metallic wheels. The size of the mounting plate is 4 x 3". See attached photos. Shipping is to the lower 48 states via USPS, UPS, or FedEx. International shipping is also available using eBay's global shipping program.