3-1/8" wheel in cast zinc housing-exterior mount (sold individually)Product I.D.: 7CASRECMETALZNCHWheel diameter: 3-1/8"Wheel tread width: 7/8"Product Material: Cast zinc alloy, natural silver finish, black, hard resin inline skate wheelOur interior corner mounted caster assembly incorporates a high strength cast zinc alloy housing that screws or rivets into left & right corners of structure you intend rolling. This part is often used in conjunction with our product I.D. 4HARHANPULL3STG or 4HARHANDPULLEXT retractable tow handles as well as our 4HARRUBFT791CH heavy-duty rubber feet for leveling purposes. Weight capacity per pair of our corner mount, recessed casters is recommended not to exceed 75 pounds.